Real-world effectiveness of COVID-19 vaccines: a literature review and meta-analysis

Protection and waning of vaccine-induced, natural and hybrid immunity to SARS-CoV-2 in Hong Kong

BACKGROUND

As the COVID-19 pandemic transitions into its fourth year, understanding the dynamics of immunity is critical for implementing effective public health measures. This study examines vaccine-induced, natural, and hybrid immunity to SARS-CoV-2 in Hong Kong, focusing on their protective effectiveness and waning characteristics against infection during the Omicron BA.1/2 dominant period.

RESEARCH DESIGN AND METHODS

We conducted a territory-wide retrospective cohort study using vaccination and infection records from the Hong Kong Department of Health. The analysis included over 6.5 million adults, applying the Andersen-Gill model to estimate protective effectiveness while addressing selection bias through inverse probability weighting.

RESULTS

Vaccine-induced immunity peaked one month after the first dose but waned rapidly, while boosters significantly prolonged protection. Infection-induced immunity showed higher initial effectiveness but declined faster than vaccine-induced immunity. Hybrid immunity provided the most durable protection. mRNA vaccines (Comirnaty) demonstrated greater effectiveness and slower waning compared to inactivated vaccines (CoronaVac).

CONCLUSIONS

Hybrid immunity represents the most effective strategy for sustained protection against SARS-CoV-2. Public health policies should emphasize booster campaigns and hybrid immunity pathways to enhance population-level immunity and guide future COVID-19 management in Hong Kong.

Efficacy and limitations of SARS-CoV-2 vaccines - A systematic review

The emergence of the SARS-CoV-2 virus worldwide led to the call for the development of effective and safe vaccines to contain the spread and effects of COVID-19. Using information from 40 publications, including clinical trials and observational studies from 2019 to 2024, this review assesses the effectiveness, safety, and limitations of four major vaccines: Sinopharm (BBIBP-CorV), Moderna (mRNA-1273), Pfizer-BioNTech (BNT162b2), and CoronaVac. Pfizer-BioNTech and Moderna's mRNA vaccines proved to be more effective than others; Moderna's vaccines showed an efficacy of 94.1 % against symptomatic infection, while Pfizer-BioNTech's vaccines showed an efficacy of up to 95 %, against severe diseases and hospitalization. These vaccinations, which included protection against Omicron and Delta variants, offered notable protection against serious illness, hospitalization, and mortality. Severe adverse events were rare while most adverse events were mild to moderate, such as headaches, fatigue, and localized reactions. In contrast, inactivated virus vaccines such as Sinopharm and CoronaVac with efficacies ranging from 50 to 79 % against symptomatic infection showed lower levels of effectiveness. In Phase 3 trial, Sinopharm showed 72.8 % efficacy, whereas CoronaVac demonstrated roughly 67 % efficacy in population against hospitalization and severe disease. Booster doses were required for adequate immunological response, especially against novel strains, as these vaccinations proved to be less effective in older populations. They showed considerable safety profiles, with mild side effects, but their low immunogenicity is concerning. This review emphasizes the importance of continuously evaluating vaccines in response to the evolving virus, essential for improving international immunization programs.

Vaccine effectiveness of inactivated and mRNA COVID-19 vaccine platform during Delta and Omicron wave in Jakarta, Indonesia: A test-negative case-control study

BACKGROUND

Vaccination was included in the Indonesian government policy to address Delta and Omicron waves of SAR-CoV-2 infections. This study assesses the effectiveness of inactivated (CoronaVac, BBIBP-Cor) and mRNA vaccines (mRNA-1273, BNT162b2) against COVID-19 regardless of symptoms and fatal COVID-19 (mortality within 30 days after confirmed RT-PCR) during Delta and Omicron period in Jakarta, Indonesia.

METHODS

This study case-control, test-negative study included all individuals aged over 18 years in Jakarta with complete and consistent SARS-CoV-2 RT-PCR results from 1 June to 31 August 2021 (Delta period) and 1 January to 2 April 2022 (Omicron period), as well as complete vaccination status. This study integrates several public health data from the Jakarta provincial government. From the odds ratio, vaccine effectiveness (VE) was analyzed as the primary outcome using unmatched analysis, matched analysis, and adjustments for other factors.

RESULTS

This study includes 982,885 eligible subjects recorded from March 2021 to April 2022. All subjects generally underwent testing 4-9 weeks after their last vaccine dose. The VE of 2-dose inactivated vaccine against SARS-CoV-2 infection during Delta wave was 22.06% (95% CI 20.63-24.54) and the VE against fatal COVID-19 was 78.55% (95% CI 72.91-83.00). A complete primary dose of mRNA vaccine showed VE of 24.81% (95% CI 16.81-32.09) against infection during Omicron wave. Furthermore an additional mRNA booster dose showed VE of 68.82% (95% CI 54.11-78.82) based on unmatched analysis.

CONCLUSION

A complete primary dose of inactivated vaccine provided mild protection against COVID-19 and essential protection against fatal cases during the Delta wave, but offered little to no protection during the Omicron wave. In contrast, the mRNA vaccine, either as primary vaccination, homologous, or heterologous booster regimen, conferred acceptable protection against Omicron. This study recommends real-world vaccination strategies for LMICs with typical vaccine supply constraints.

Did COVID-19 surveillance system sensitivity change after Omicron? a retrospective observational study in England

BACKGROUND

During the COVID-19 pandemic in England, increases and falls in COVID-19 cases were monitored using many surveillance systems (SS). However, surveillance sensitivity may have changed as different variants were introduced to the population, due to greater disease-resistance after comprehensive vaccination programmes and widespread natural infection or for other reasons.

METHODS

Time series data from ten epidemic trackers in England that were available Sept 2021-June 2022 were compared to each other using Spearman correlation statistics. Least biased and most timely SS in England were identified as 'best' standard epidemic trackers, while other COVID-19 tracking datasets we denote as complementary trackers. We compared the best standard trackers with each other and with the complementary trackers. Correlation calculations with 95% confidence intervals were made between complementary and best standard epidemic trackers. We tested the hypothesis that correlation with the best trackers was especially poor during transition periods when Delta, Omicron BA.1 and Omicron BA.2 sublineages were each dominant. Daily ascertainment percentages of incident cases that each SS detected during each variant's dominance were calculated. We tested for statistically significant (at p < 0.05) differences in the distribution of the ascertainment values during each COVID-19 variant's dominance, using Welch's oneway ANOVA.

RESULTS

Spearman rho correlation was significantly positive between most complementary and the best trackers over the whole period. There was no apparent visual indication that correlations were especially poor during transition period from Delta to BA.1. There were falls in correlation in the transition period from BA.1 to BA.2 but these falls were relatively small compared to correlation fluctuations over the full period. Ascertainment was highest in the Delta period for complementary systems against the least biased tracker of incidence. Ascertainment was statistically different between the three variant-dominant periods.

CONCLUSIONS

From September 2021 to June 2022, complementary SS generally reflected case rises and falls. Ascertainment was highest in the Delta-dominant period but no complementary tracker was highly stable. Factors other than which variant was dominant seem likely to have affected how well each tracker reflected true case rises and falls.

The path to prevention of multiple sclerosis: Considerations for Epstein-Barr virus vaccine-based prevention studies

Recent advancements in our understanding of the association between Epstein-Barr virus (EBV) and multiple sclerosis (MS), along with progress in EBV vaccine development, warrant serious considerations of future EBV vaccine-based MS-prevention studies. The clinical, financial, logistical, and technological considerations for designing and conducting retrospective and/or prospective prevention studies with the primary objective of evaluating the effectiveness of EBV vaccines in preventing MS and other EBV-associated sequelae are presented here. As implementation of these studies may require hundreds of thousands of participants, millions of dollars, and decades to observe if meaningful reductions in MS incidence occur, alternative approaches using pragmatic phase IV, post-licensure study designs focused on either the prevention of MS or infectious mononucleosis (IM), a common clinical manifestation of EBV infection that has been associated with increased risk of MS, are also explored. Current knowledge gaps in technology, funding, and research that must be addressed for a study protocol to be successfully designed and implemented are also discussed.

Anti-vaccine attitudes and COVID-19 vaccine status at the end of the U.S. public health emergency

INTRODUCTION

Despite the end of the federal COVID-19 public health emergency in May 2023, COVID-19 prevention remains a priority. This study investigates how public vaccination attitudes and perceived COVID-19 risks relate to vaccination status, aiming to identify factors associated with COVID-19 vaccination post-emergency.

METHODS

An online survey was conducted from April to May 2023 among a non-representative, nationally-based sample of MTurk workers. The primary outcome was COVID-19 vaccination status. Variables examined included anti-vaccine attitudes, health status, COVID-19 experiences, and sociodemographic factors. We created a composite measure of anti-vaccine attitudes from 15 items with three levels. Bivariate tests of association and multivariable logistic regression were performed.

RESULTS

A final sample of 989 adults were included in this analysis. In our multivariable model, individuals with higher anti-vaccine attitudes were less likely to be vaccinated against COVID-19 compared to those with low anti-vaccine attitudes (OR = 0.10, 95 % CI 0.04, 0.25). Those who identified as LGBQ+ (OR = 2.55, 95 % CI 1.32, 4.94), had chronic conditions (OR = 2.94, 95 % CI 1.43, 6.01) and had felt stigmatized from COVID-19 infections (OR = 3.33, 95 % CI 1.47, 7.58) were more likely to be vaccinated, even after adjusting for anti-vaccine attitudes. News source, perceived risk of contagion by contact, and long COVID-related factors were not significantly associated with vaccination status in the multivariable model.

DISCUSSION

Our findings highlight the persistent relationship between anti-vaccine attitudes and vaccination status in the "post-pandemic" era. Beyond vaccine attitudes, sexual orientation, chronic conditions, and stigmatization experiences may influence perceived need for protection. Stigma can sometimes reinforce social norms driving vaccination, but this effect is nuanced, particularly with anti-vaccine attitudes. To promote vaccine uptake, interventions should prioritize community support, counter misinformation, and enhance vaccine literacy. Building trust among vulnerable populations is essential, rather than relying on public health messaging that may reinforce social stigma.

Barriers to initial COVID-19 booster among US adults who completed a primary vaccine series in the CHASING COVID cohort, September 2021-October 2022

It is crucial to understand factors associated with COVID-19 booster uptake in the United States given the updated COVID-19 vaccine recommendations. Using data from a national prospective cohort (n = 4616) between September 2021 and October 2022, we examined socioeconomic, demographic, and behavioral factors of initial booster uptake among participants fully vaccinated with the primary COVID-19 vaccines series. Cox proportional hazards models were used to estimate the associations of each factor with time to initial booster uptake. Most participants (86.5%) reported receiving their initial booster. After adjusting for age, race/ethnicity, education, region, and employment, participants with greater risk for severe COVID-19 had similar booster uptake compared with those with lower risk (adjusted hazard ratio [aHR], 1.04; 95% CI, 0.95-1.14). Participants with greater barriers to healthcare (aHR, 0.89; 95% CI, 0.84-0.96), food insecurity (aHR, 0.82; 95% CI, 0.75-0.89), and housing instability (aHR, 0.81; 95% CI, 0.73-0.90) were less likely to report receiving initial booster compared with those without those barriers. Factors motivating the decision to vaccinate changed from safety-related concerns for the primary series to perceived need for the booster. It is key to address economic and health access barriers to achieve equitable COVID-19 vaccine uptake and continued protection against COVID-19.

Applying the health belief model (HBM) to understand COVID-19 vaccine uptake among youth and young adults: Findings from a 6-month follow-up study in the United States

BACKGROUND

Vaccination is one of the most effective strategies for COVID-19 prevention. Monitoring and increasing vaccine uptake among youth and young adults (YYA) not only prevents the spread of the disease but also protects their health and well-being from serious COVID-19 illness. This study applied the health belief model (HBM) to understand the predictors of COVID-19 vaccine uptake among YYA in the United States.

METHODS

In early 2021, we conducted a national, online survey among diverse YYA aged 14 to 24 years in the United States. Between July 2021 and September 2022, this study followed participants who were not vaccinated for six months to learn about their vaccine status and prevention behaviors (N = 245). We explored the prevalence of COVID-19 vaccination among YYA by age, race/ethnicity, and sexual and gender identities. Multivariable logistic regression models were performed to estimate associations between HBM constructs and COVID-19 vaccination.

RESULTS

The majority of participants had received a vaccine. (80.8 %). We observed significant differences in COVID-19 vaccination uptake by age; those aged 18 to 21 years were over 3 times as likely to report receiving a vaccine. Regarding the HBM constructs, we found that health motivation, perceived benefits, and protection self-efficacy were significantly associated with vaccine uptake among YYA.

CONCLUSION

This study highlights the effectiveness of HBM in understanding COVID-19 vaccine uptake among YYA in the United States. The findings suggest that health motivation, perceived benefits of vaccination, and protection self-efficacy are key factors driving vaccine uptake in this demographic. Significant age differences in vaccination rates indicate that targeted interventions for younger age groups, particularly those aged 14 to 17 years, may be necessary to increase vaccination coverage. These insights can inform future public health strategies to improve vaccine acceptance and uptake, ensuring better health outcomes and protection against future public health crises in YYA populations.

Effect of heterologous intranasal iNCOVACC® vaccination as a booster to two-dose intramuscular Covid-19 vaccination series: a randomized phase 3 clinical trial

BACKGROUND

Due to waning immunity and emerging variants, protection following primary intramuscular Covid-19 vaccinations is decreasing, so health agencies have been proposing heterologous booster vaccinations. Here, we report immunogenicity and safety evaluation of heterologous booster vaccination with an intranasal, adenovirus vectored SARS-CoV-2 vaccine (BBV154) in healthy adults, who were previously primed with two doses of either Covaxin® or Covishield™. We compare results with use of a homologous booster vaccination combination.

METHODS

This was a randomized, open-label phase 3 trial conducted to evaluate immunogenicity and safety of a booster dose of intranasal BBV154 vaccine or intramuscular EUA approved Covid-19 vacines in India. Healthy participants of ≥18 years age with no history of SARS-CoV-2 infection, who received two doses of Covaxin® or Covishield™ at least 6 ± 1 months earlier were enrolled. The primary outcome was the neutralising antibody titers against wild-type virus using a plaque-reduction neutralization test (PRNT50). Other outcomes measured were humoral (IgG), mucosal (IgA) and cell mediated responses. The protocol was registered #NCT05567471 and approved by National Regulatory Authority (India) #CTRI/2022/02/039992.

RESULTS

In this phase 3 trial, a total of 875 participants were randomized into 5 Groups in a ratio of 2:1:2:1:1 to receive either booster dose of BBV154 or Covaxin or Covishield. Based on per-protocol population, at Day 56, neutralization antibody titres were 564.1 (479·1, 664·1), 578.1 (436·9, 764·9), 655.5 (533·3, 805·8), 625.4 (474·7, 824·0), 650.1 (519·7, 813·1) for Group 1 to 5 respectively. This study was conducted, whilst the Omicron variant was prevalent. There were varying levels of severity of infection across different study sites with varied baseline antibody titers. Consequently, the average neutralization (PRNT50) antibody titers are similar across all Groups on day 56 and exhibited large differences within the Group, depending on the study site. All booster vaccinations are well tolerated and reported no serious adverse events; in particular, study participants boosted with BBV154 had significantly fewer solicited local adverse events than those primed and boosted with Covishield.

CONCLUSIONS

These findings demonstrate that impact of booster across different cohorts is governed by infection status of the individual and geographical diversity, thus necessitating large cohorts, well distributed studies before Covid-19 booster effects are interpreted.

Factors Associated With the Transmission of the Delta Severe Acute Respiratory Syndrome Coronavirus 2 Variant in Households: The Israeli COVID-19 Family Study (ICoFS)

Understanding how interpersonal interactions and immunological factors shape severe acute respiratory syndrome coronavirus 2 transmission in households is crucial for designing control measures. We developed a Bayesian data augmentation transmission model to evaluate the effects of isolation, parental care, and vaccine-induced immunity on Delta variant transmission from the follow-up of 1093 Israeli households (July-August 2021). Among the 2883 household contacts, 1096 (38%) were infected. Children were 38% (95% Credibleconfidence interval [CrI], 7%-81%) more likely to be infected than adults. Isolation measures reduced transmission by 52% (95% CrI, 46%-57%). Transmission was 39% (95% CrI, 11%-76%) higher between children and female adults than between children and male adults. Vaccine effectiveness was 78% (95% CrI, 54%-90%), 85% (95% CrI, 70%-94%), and 73% (95% CrI, 49%-88%), respectively, for 1, 2, and 3 recent vaccine doses (within ≤90 days) but dropped to 18% (95% 95% CrI, -6% to 36%) for 2 doses administered >90 days earlier. Household member interactions significantly shaped transmission, and isolation measures effectively reduced transmission.

Immunization thresholds to change the overall level and the effect of cases on deaths by COVID-19 in pregnant and postpartum women

Since the first officially reported case of COVID-19, the scientific community has spent much of its time understanding the dynamics of the virus. Several studies have indicated that some population segments are especially susceptible to COVID-19 complications, including pregnant and postpartum women. Although recommendations such as social distancing, proper sanitation, and the use of protection masks were crucial in slowing down the virus dissemination, the protection provided by vaccination is undeniable, especially for this particular group. Concerning deaths by COVID-19, it is natural to assume that daily deaths are related to reported hospitalized cases and to expect that, as vaccination increases, this effect gradually decreases. As far as we know, no other studies have addressed this issue. Therefore, this study introduces a novel generalized linear model with segmented interaction to fill this gap. The model was used to estimate the vaccination thresholds required to change the overall level and the daily hospitalized cases effect on daily deaths from COVID-19 in pregnant and postpartum women reported between January 3rd, 2021, and January 1st, 2022. Inference methods for the proposed model were developed. The results obtained indicate that, in the first period from May 25th to July 1st, 2021 (between 14,420 and 271,570 first doses, respectively), vaccination caused a significant gradual decrease in the effect of reported hospitalized cases on fatalities and, in a second period from July 25th to October 13th, 2021 (between 653,150 and 968,880 first doses, respectively), it induced a gradual reduction of the overall level of deaths. Using the average number of cases as a reference, during the period of observations, the expected number of deaths reduced from 6.16 to 0.36, a decrease of 94.16%. The importance of learning from COVID-19 data must be highlighted, as it provides us with critical insights to better prepare for future health crises.

COVID-19 severity and vaccine effectiveness in Malawi: A test-negative case-control study

Background

COVID-19 vaccines were administered globally, and Malawi commenced vaccination on 11 March 2021.

Aim

This study assessed the real-world effectiveness of COVID-19 vaccines and factors associated with disease severity and mortality in Malawi.

Setting

A facility-based case-control study within the largest referral hospitals.

Methods

Cases (COVID-19 positive) were matched 1:1 with controls based on age, sex and testing date. Interviews via phone focused on COVID-19 testing and vaccination, underlying conditions and disease outcomes. Analysed using STATA 17, the exposure of interest was vaccination status. For vaccine effectiveness (VE), conditional logistic regression modelling was used, while disease severity and management were analysed using binary logistic regression.

Results

The unvaccinated were at 53.3%, and 35.8% were fully vaccinated and/or received a booster. The VE among the fully and partially vaccinated was 10% (95% CI: -26.2, 35.81) and 31.8% (95% CI: -9.91, 57.72), respectively compared to the unvaccinated. Most of the COVID-19 patients (87.8%) were not hospitalised. Underlying chronic conditions and a previous positive COVID-19 test were associated with severe disease (aOR: 3.54, 95% CI: 1.65, 7.61 and aOR: 2.73, 95% CI: 1.13, 7.61, respectively); however, these odds were not different by vaccination status.

Conclusion

The VE was low and severe disease was linked with chronic illnesses and previous positive COVID-19 tests. Efforts to promote vaccination through education and access should be enhanced, particularly for those with underlying chronic conditions.

Contribution

The findings can inform strategies on prioritisation for disease vaccination and improving patient outcomes.

Modeling vaccination prioritization strategies for post-pandemic COVID-19 in the Republic of Korea accounting for under-reporting and age-structure

BACKGROUND

Vaccination has played a key role in limiting the impacts of COVID-19. Even though the acute phase of the COVID-19 pandemic is now over, the potential for substantial numbers of cases and deaths due to novel SARS-CoV-2 variants remains. In the Republic of Korea, a strategy of vaccinating individuals in high-risk groups annually began in October 2023.

METHODS

We used mathematical modeling to assess the effectiveness of alternative vaccination strategies under different assumptions about the number of available vaccine doses. An age-structured transmission model was developed using vaccination and seropositivity data. Various vaccination scenarios were considered, taking into account the effect of undetected or unreported cases (with different levels of reporting by age group): S1: prioritizing vaccination towards the oldest individuals; S2: prioritizing vaccination towards the youngest individuals; and S3: spreading vaccines among all age groups.

RESULTS

Our analysis reveals three key findings. First, administering vaccines to older age groups reduces the number of deaths, while instead targeting younger individuals reduces the number of infections. Second, with approximately 6,000,000 doses available annually, it is recommended that older age groups are prioritized for vaccination, achieving a substantial reduction in the number of deaths compared to a scenario without vaccination. Finally, since case detection (and subsequent isolation) affects transmission, the number of cumulative cases was found to be affected substantially by changes in the reporting rate.

CONCLUSIONS

In conclusion, vaccination and case detection (facilitated by contact tracing) both play important roles in limiting the impacts of COVID-19. The mathematical modeling approach presented here provides a framework for assessing the effectiveness of different vaccination strategies in scenarios with limited vaccine supply.

Therapeutic plasma exchange for fibrinogen-associated hyperviscosity: results of the COVID-19 PLasma EXchange (COPLEX) randomized controlled trial

BACKGROUND

Therapeutic plasma exchange (TPE) is the primary intervention for treating symptomatic hyperviscosity from hypergammaglobulinemia, yet its efficacy for treating hyperviscosity related to hyperfibrinogenemia is unclear.

OBJECTIVES

Define the safety and efficacy of TPE for critically ill COVID-19 patients with elevated blood viscosity from hyperfibrinogenemia.

METHODS

We performed a prospective randomized controlled trial in critically ill COVID-19 patients in a single US healthcare system. Patients with hyperfibrinogenemia (>800 mg/dL) or elevated plasma viscosity (2.3-3.5 centipoise [cP]) were randomized to receive TPE on 2 consecutive days or continued standard of care (SOC).

RESULTS

Twenty participants were enrolled, with 10 receiving TPE and 10 receiving SOC alone. Mean (±SEM) plasma viscosity decreased significantly from 2.35 cP (±0.12) to 1.61 cP (±0.03) in the TPE group and was unchanged in the SOC group (2.47 cP [±0.11] to 2.47 cP [±0.15]). Mean fibrinogen decreased from 934.0 mg/dL (±25.1) to 359.1 mg/dL (±22.5) after TPE vs from 859.6 mg/dL (±57.6) to 807.3 mg/dL (±63.1) in SOC. There was no significant difference in 28-day all-cause mortality between groups, with 2 deaths in the TPE cohort and 5 deaths in the SOC cohort (P = .13). No serious safety events related to TPE were reported. TPE significantly decreased biomarkers of inflammation (erythrocyte sedimentation rate and C-reactive protein) and endothelial activation (von Willebrand factor and factor VIII) but not hemostatic activation (prothrombin fragment 1.2, thrombin-antithrombin complex, and fibrin monomer) or immunoglobulin (IgG and IgM) levels.

CONCLUSION

TPE is safe and effective for normalizing elevated blood viscosity from hyperfibrinogenemia in COVID-19 patients. Additional studies are needed to determine the impact of TPE on overall patient outcomes, including in those with non-COVID-19 conditions associated with hyperfibrinogenemia.

COVID-19 vaccination: 2023 Taiwan Association of Gerontology and Geriatrics (TAGG) consensus statements

The COVID-19 pandemic remains challenging due to the rapid evolution of the severe acute respiratory syndrome coronavirus 2. This article discusses recent findings on high-risk groups for COVID-19 mortality and morbidity, along with consensus statements from the 2023 Taiwan Association of Gerontology and Geriatrics (TAGG) meeting. It examines evidence on viral mutation mechanisms, emerging variants, and their implications for vaccination strategies. The article underscores advanced age, immunocompromised status, chronic medical conditions, occupational exposure, and socioeconomic disparities as significant risk factors for severe COVID-19 outcomes. TAGG's consensus emphasizes robust vaccination promotion, prioritizing elderly, and immunocompromised groups, individualized multi-dose regimens for immunocompromised patients, and simplified clinical guidelines. Discussions on global and regional recommendations for regular, variant-adapted boosters highlight the non-seasonal nature of COVID-19. Key agreements include escalating domestic preparedness, implementing vigorous risk-based vaccination, and adapting global guidelines to local contexts. Given ongoing viral evolution, proactive adjustment of vaccination policies is essential. Scientific consensus, tailored recommendations, and rapid knowledge dissemination are vital for optimizing COVID-19 protection among vulnerable groups in Taiwan. This article seeks to inform clinical practice and public health policy by summarizing expert-driven vaccination perspectives.

Age- and disease severity-associated changes in the nasopharyngeal microbiota of COVID-19 patients

Although many studies have associated changes in the nasopharyngeal microbiota to patient's susceptibility to COVID-19, their results are highly variable and contradictory. Addressing the limitations in previous research responsible for that variability, this study uses 16S rRNA gene sequencing to analyze the nasopharyngeal microbiota of 395 subjects, 117 controls, and 278 COVID-19 patients, of different age groups that cover the entire lifespan and across varying disease severities. This revealed that bacterial alpha diversity decreases progressively throughout life but only in severely ill COVID-19 patients, in whose nasopharynx, moreover, several opportunistic pathogen bacterial genera are overrepresented. Notably, Scardovia wiggsiae appears only in severe COVID-19 patients over 60 years of age, suggesting its potential utility as a COVID-19 severity biomarker in the elderly, who are the most susceptible individuals to suffer from serious forms of the disease. Thus, our results provide valuable insights into age-associated dynamics within nasopharyngeal microbiota during severe COVID-19.

SARS-CoV-2 vaccination reduces the risk of thrombotic complications in severe COVID-19

OBJECTIVES

The aim of this study was to evaluate the association between SARS-CoV-2 vaccination and the occurrence of thrombotic complications in patients admitted to intensive care for severe COVID-19 pneumonia.

DESIGN

Observational, descriptive, prospective, multicentre study.

SETTING

Intensive care units of five university hospitals.

PATIENTS

A total of 255 patients admitted to the intensive care unit (ICU) with SARS-CoV-2 pneumonia, confirmed by RT-PCR in throat swab or tracheal aspirate, starting the date the first vaccinated patient against SARS-CoV-2 was admitted in one of the participating ICUs, were included in the analysis.

MAIN VARIABLES OF INTEREST

Vaccination status against SARS-CoV-2 and thrombotic events.

RESULTS

18.8% of patients had received some form of vaccination. Thrombotic events occurred in 21.2% of patients. Lack of vaccination was associated with thrombotic events (OR 5.024; 95% CI: 1.104-23.123; p = 0.0037) and death (OR 5.161; 95% CI: 1.075-24.787; p = 0.04). ICU mortality was not associated with the occurrence of thrombotic complications.

CONCLUSIONS

In this series of patients, vaccination against SARS-CoV-2 reduced the risk of thrombotic events and mortality in patients with severe COVID-19 admitted to the ICU. Thrombotic complications did not alter ICU mortality.

COVID-19 related complications

The COVID-19 pandemic has significantly impacted global healthcare systems, revealed vulnerabilities and prompted a re-evaluation of medical practices. Acute complications from the virus, including cardiovascular and neurological issues, have underscored the necessity for timely medical interventions. Advances in diagnostic methods and personalized therapies have been pivotal in mitigating severe outcomes. Additionally, Long COVID has emerged as a complex challenge, affecting various body systems and leading to respiratory, cardiovascular, neurological, psychological, and musculoskeletal problems. This broad spectrum of complications highlights the importance of multidisciplinary management approaches that prioritize therapy, rehabilitation, and patient-centered care. Vulnerable populations such as paediatric patients, pregnant women, and immunocompromised individuals face unique risks and complications, necessitating continuous monitoring and tailored management strategies to reduce morbidity and mortality associated with COVID-19.

Prospective cohort study of fatigue before and after SARS-CoV-2 infection in the Netherlands

Fatigue is one of the most common persistent symptoms of SARS-CoV-2 infection. We aimed to assess fatigue during and after a SARS-CoV-2 infection by age, sex, presence of a medical risk condition, SARS-CoV-2 variant and vaccination status, accounting for pre-infection fatigue and compared with uninfected individuals. We used data from an ongoing prospective cohort study in the Netherlands (VASCO). We included 22,705 first infections reported between 12 July 2021 and 9 March 2024. Mean fatigue scores increased during infection, declined rapidly in the first 90 days post-infection, but remained elevated until at least 270 days for Delta and 120 days for Omicron infections. Prevalence of severe fatigue was 18.5% before first infection. It increased to 24.4% and 22.5% during acute infection and decreased to 21.2% and 18.9% at 90 days after Delta and Omicron infection, respectively. The prevalence among uninfected participants was lower than among matched Delta-infected participants during the acute phase of the infection and 90 days post-infection. For matched Omicron-infected individuals this was only observed during the acute phase. We observed no differences in mean post- vs pre-infection fatigue scores at 90-270 days post-infection by vaccination status. The impact of SARS-CoV-2 infection on the prevalence of severe fatigue was modest at population level, especially for Omicron.

N-acetyl-cysteine in Intensive Care Unit Patients with Acute Respiratory Distress Syndrome due to COVID-19: A Retrospective Cohort Study

COVID-19-related acute respiratory distress syndrome (ARDS) is linked to mortality, primarily due to a cytokine storm, oxidative stress imbalance, and pro-thrombotic state.PurposeWe assessed the potential association between N-acetyl-cysteine (NAC) and clinical outcomes in critically ill subjects with COVID-19-related ARDS.Material and MethodsWe included subjects with confirmed COVID-19 who were admitted to our ICU between March 1, 2020, and January 31, 2021, due to ARDS and necessitating invasive mechanical ventilation (IMV). Subjects who received standard of care (SOC) were compared with subjects who additionally received NAC 600 mg bid orally.ResultsA total of 243 subjects were included in this study. The results indicate significantly improved survival rates in the NAC plus SOC group, both in the unadjusted analysis and after adjusting for confounding factors such as ARDS severity (HR 0.48, 95% CI 0.32-0.70).ConclusionsWe found that oral administration of NAC was associated with reduced mortality in critically ill patients with COVID-19 related ARDS.

Comparative effectiveness of three common SARS-COV-2 vaccines: A network meta-analysis of randomized trials

BACKGROUND

Moderna, Pfizer, and AstraZeneca SARS-CoV-2 vaccines for preventing COVID-19 have regulatory approval in most countries. We conducted a network meta-analysis to compare their effectiveness.

METHODS

We searched PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), ICTRP, and Clinicaltrials.gov for the randomized controlled trials (RCTs) published between 1st January 2020 and 1st February 2024. Eligible RCTs evaluated the Moderna, Pfizer or AstraZeneca vaccines among healthy individuals and reported the effectiveness of vaccination versus control measured with the outcome occurrence of COVID-19. We performed study selection, data extraction, and quality (risk of bias) assessment in duplicate. Network meta-analysis with random effects models was used to generate odds ratios (OR) with 95% confidence intervals (CI), evaluating heterogeneity statistically using I2 for direct comparisons and ranking vaccines hierarchically using the surface under the cumulative ranking curve (SUCRA). This study was registered on PROSPERO, CRD42023457957.

FINDINGS

Of the 1954 initial citation, 18 RCTs (272,724 participants; 151,034 received one of the vaccines and 121,690 controls) that reported the outcome occurrence of COVID-19 were selected. Of these, 2 (11%) were moderate and 5 (28%) were high in quality. In network meta-analysis, all three vaccines were effective compared directly with control (Moderna OR 0.13, 95% CI 0.07-0.26, I2 97%; Pfizer OR 0.10, 95% CI 0.05-0.19, I2 78%; AstraZeneca OR 0.38, 95% CI 0.25-0.59, I2 63%). Indirect comparison of vaccines using control as the common comparator showed that AstraZeneca was less effective than Moderna (OR 2.84, 95% CI 1.32-6.12) and Pfizer (OR 3.94, 95% CI 1.80-8.60), while Moderna versus Pfizer showed no difference (OR 1.39, 95% CI 0.56-3.46). Vaccine SUCRA probabilities were higher for Pfizer than Moderna and AstraZeneca (92%, 75% and 33% respectively compared to control).

INTERPRETATIONS

Pfizer ranks highest followed by Moderna (without a statistically significant difference) and AstraZeneca vaccines for preventing symptomatic COVID-19.

Novel Vaccines Targeting the Highly Conserved SARS-CoV-2 ORF3a Ectodomain Elicit Immunogenicity in Mouse Models

BACKGROUND

The majority of antigen-based SARS-CoV-2 (SCV2) vaccines utilized in the clinic have had the Spike protein or domains thereof as the immunogen. While the Spike protein is highly immunogenic, it is also subject to genetic drift over time, which has led to a series of variants of concern that continue to evolve, requiring yearly updates to the vaccine formulations. In this study, we investigate the potential of the N-terminal ectodomain of the ORF3a protein encoded by the orf3a gene of SCV2 to be an evolution-resistant vaccine antigen. This domain is highly conserved over time, and, unlike many other SCV2 conserved proteins, it is present on the exterior of the virion, making it accessible to antibodies. ORF3a is also important for eliciting robust anti-SARS-CoV-2 T-cell responses.

METHODS

We designed a DNA vaccine by fusing the N-terminal ectodomain of orf3a to macrophage-inflammatory protein 3α (MIP3α), which is a chemokine utilized in our laboratory that enhances vaccine immunogenicity by targeting an antigen to its receptor CCR6 present on immature dendritic cells. The DNA vaccine was tested in mouse immunogenicity studies, vaccinating by intramuscular (IM) electroporation and by intranasal (IN) with CpG adjuvant administrations. We also tested a peptide vaccine fusing amino acids 15-28 of the ectodomain to immunogenic carrier protein KLH, adjuvanted with Addavax.

RESULTS

The DNA IM route was able to induce 3a-specific splenic T-cell responses, showing proof of principle that the region can be immunogenic. The DNA IN route further showed that we could induce ORF3a-specific T-cell responses in the lung, which are critical for potential disease mitigation. The peptide vaccine elicited a robust anti-ORF3a antibody response systemically, as well as in the mucosa of the lungs and sinus cavity.

CONCLUSIONS

These studies collectively show that this evolutionarily stable region can be targeted by vaccination strategies, and future work will test if these vaccines, alone or in combination, can result in reduced disease burden in animal challenge models.

The protective role of vitamin D in BNT162b2 vaccine-related acute myocarditis

Introduction

Vaccine-related myocarditis is recognized as a rare but important complication, especially after mass-scale mRNA COVID-19 vaccination. Knowledge regarding how to minimize the risk is limited. As NK cells can mediate acute myocarditis after mRNA COVID-19 vaccination and vitamin D may inhibit NK cells via cytokine modulation, we hypothesize that the myocarditis side effect is related to a hypovitaminosis D - mRNA vaccine - hypercytokinemia - NK cell axis, which is amendable to clinical intervention.

Methods

Biochemical, immunophenotypic and genotyping assays were performed to examine vitamin D status and immune profiles in 60 patients who had BNT162b2 vaccine-related acute myocarditis.

Results

A high incidence of hypovitaminosis D (73.3%) was observed in these individuals with vaccine-related myocarditis, particularly in those presented with chest pain or intensive care unit (ICU) admission. Moreover, vitamin D level was negatively associated with peak serum cardiac troponin T level during vaccine-related myocarditis. Genotypically, the GC (vitamin D binding protein) rs4588T allele which encoded the GC2 isoform of vitamin D binding protein was a risk allele, whereas the GC1S isoform was protective. Mechanistically, hypovitaminosis D was associated with higher levels of cytokines pivotal for natural killer (NK) cells (particularly interleukin-1β (IL-1β), IL-12, Interferon-γ (IFN-γ), and IL-8) and higher percentage of CD69+ NK cells in blood, which in turn correlated with chest pain presentation.

Conclusion

These data support the hypothesis that vitamin D plays a crucial role in mitigating mRNA vaccine-related myocarditis by modulating proinflammatory cytokine milieu and subsequent unfavorable NK cell activation, laying a groundwork for preventive and treatment strategies.

A Systematic Review and Meta-Analysis of Low Dose Radiation Therapy for COVID-19 Pneumonia: Learnings of 4 Years Since Pandemic

COVID-19 caused a worldwide pandemic resulting in break of demand-supply chain in all aspects of healthcare, high mortality rates, and a constant quest for effective treatment modalities. Based on historical and recent evidences of anti-inflammatory effects of low dose of ionizing radiation, several healthcare professionals proposed low-dose radiation therapy (LDRT) along with ongoing pharmacological treatment for COVID-19 pneumonia. A positive response in a few initial studies led to systematic trials by increasing the number of patients in the range of 0.5-1.5 Gy. However, the concerns of radiation-induced risks were also raised in parallel. In the present article, we have highlighted the basis of LDRT for COVID-19 therapy. We have reviewed the available literature, specifically for outcomes on various clinical trials carried out with LDRT. Meta-analysis was performed to identify if any survival benefits are offered by addition of LDRT over pharmacological treatment alone among COVID-19 pneumonia patients. Other clinical recovery parameters such as intubation rates, oxygenation status, anti-inflammatory response have also been compared. Overall data trends favored LDRT with standard pharmacological treatment against control cohort which received standard treatment alone at all the endpoints in majority studies. LDRT addition resulted in significantly higher odds of survival than control cohort. Among critical and/or mechanically ventilated patients, LDRT did not show any promising outcomes over the control group. In conclusion, LDRT may serve as a promising complementary treatment modality with a potential of better prognosis, provided the patient selection criteria are critically identified and implemented.

Predictors of severity of SARS-CoV-2 infections in Brazil: Post hoc analyses of a randomised controlled trial

OBJECTIVES

To identify demographic, clinical and immunological factors associated with adverse COVID-19 outcomes.

METHODS

A large randomised controlled trial of ChAdOx1 nCoV-19 was undertaken in Brazil. Participants were randomised 1:1 either to receive ChAdOx1 nCov-19 or to a control group. COVID-19 infections were confirmed by nucleic acid amplification test (NAAT) and classified using the WHO clinical progression scale. Anti-spike antibody responses and serum neutralising activity were measured 28 days after second vaccination in some participants. Exploratory analyses were conducted into factors associated with COVID-19 infection severity and hospitalisation, using logistic regression models adjusted for demographic and clinical factors.

RESULTS

10,416 participants were enrolled; 1790 had NAAT-positive COVID-19 infection; 63 cases required hospitalisation. More severe infection was associated with greater body-mass index (BMI) (odds ratio [OR] = 1.06 [95 %CI: 1.01-1.10], p = 0.01) and diabetes (OR = 3.67 [1.59-8.07], p = 0.003). Hospitalisation risk increased with greater age (OR = 1.06 [1.03-1.08], p < 0.001) and BMI (OR = 1.10 [1.05-1.16], p < 0.001). More severe infection and hospitalisation risks increased >180 days after last vaccination. In the fully vaccinated subgroup (n = 841), only greater age predicted hospitalisation (OR = 1.07 [1.03-1.12], p < 0.001). Serological responses to two vaccine doses diminished with age.

CONCLUSIONS

Unvaccinated individuals with high BMI and diabetes risked more severe COVID-19 outcomes. Vaccination mitigated this risk.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04536051.

Consequences of COVID-19 for geriatric patients during a pandemic

To investigate the outcomes of geriatric COVID-19 patients in a German academic setting during the pandemic. This study included 468 consecutive geriatric patients (≥ 70 years) who tested positive for SARS-CoV-2 and were treated at the University of Duisburg-Essen from 2/2020 to 3/2021. 74 patients were transferred to a geriatric hospital and a 12-month follow-up (prospective study) was performed in 51 patients. Clinical assessments evaluated depression (GDS), apathy (AES), cognitive status (MMST), mobility (TUG), health status (EQ-5D-5 L), and daily living activities (Barthel Index). Demographic and clinical data were also analyzed. Results showed that the mortality in this vulnerable group was 52% (n = 209). Long-term survival was higher in patients who received comprehensive geriatric treatment (74.3% vs. 51.8%). The duration of inpatient stay at the primary hospital was 13.3 ± 3.6 days, with 28.8% (n = 135) requiring intensive care. At the 12-month mark more patients with geriatric treatment lived in nursing homes. Barthel-Index/Timed-Up-and-Go-Test/MMST/AES/GDS, and EQ-5D-5 L indicated worse outcomes in the group who received geriatric treatment. Specialized geriatric care may improve survival in geriatric COVID-19 patients despite decreased long-term outcomes. Further research, including international studies like NAPKON, are encouraged to confirm these findings and explore potential interventions for improved outcomes in this vulnerable population.

SARS-CoV-2 infection and vaccination status in six ethnic groups in Amsterdam, The Netherlands, May to November 2022

We studied severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and vaccination status among six ethnic groups in Amsterdam, the Netherlands. We analysed participants of the Healthy Life in an Urban Setting cohort who were tested for SARS-CoV-2 spike protein antibodies between 17 May and 21 November 2022. We categorized participants with antibodies as only infected, only vaccinated (≥1 dose), or both infected and vaccinated, based on self-reported prior infection and vaccination status and previous seroprevalence data. We compared infection and vaccination status between ethnic groups using multivariable, multinomial logistic regression. Of the 1,482 included participants, 98.5% had SARS-CoV-2 antibodies (P between ethnic groups = 0.899). Being previously infected and vaccinated ranged from 41.5% (95% confidence interval (CI) = 35.0-47.9%) in the African Surinamese to 67.1% (95% CI = 59.1-75.0%) in the Turkish group. Compared to participants of Dutch origin, participants of South-Asian Surinamese (adjusted odds ratio (aOR) = 3.31, 95% CI = 1.50-7.31)), African Surinamese (aOR = 10.41, 95% CI = 5.17-20.94), Turkish (aOR = 3.74, 95% CI = 1.52-9.20), or Moroccan (aOR = 15.24, 95% CI = 6.70-34.65) origin were more likely to be only infected than infected and vaccinated, after adjusting for age, sex, household size, trust in the government's response to the pandemic, and month of study visit. SARS-CoV-2 infection and vaccination status varied across ethnic groups, particularly regarding non-vaccination. As hybrid immunity is most protective against coronavirus disease 2019, future vaccination campaigns should encourage vaccination uptake in specific demographic groups with only infection.

The effectiveness of vaccines against COVID-19 in Mexico: A time series approach

OBJECTIVE

To estimate the effectiveness of several vaccine brands-Pfizer, Astra, and Sinovac-against symptomatic COVID-19 without information on vaccination at the individual level.

METHODS

We use data of mass vaccination programs-specifically, for sexagenarians and quinquagenarians-in three large municipalities of Mexico (Monterrey, Guadalupe, and San Nicolás) to conduct a two-step time series estimation procedure involving a synthetic control group. The data covers the period between the first week of March 2020 and the first week of October 2021.

RESULTS

Vaccine effectiveness is a concave function of time. At the peak, Pfizer reaches 92.6 % effectiveness, Astra 83.6 % and Sinovac 65.6 %. This occurs 9 to 12 weeks after the first shot.

CONCLUSION

The results indicate that the three vaccines protect against symptomatic COVID-19. Nevertheless, they offer different levels of protection. The results also suggest that VE-under a two-shot scheme-reaches its peak 9 to 16 weeks after the first shot. Moreover, there seems to be a trade-off between achieving higher efficiency by administering the 2nd shot earlier or extending the protection period by administering it later.

COVID-19 Vaccines Effectiveness and Safety in Trinidad and Tobago: A Systematic Review and Meta-Analysis

This systematic review evaluated the effectiveness and side effects of various COVID-19 vaccines, with a focus on Trinidad and Tobago. The Pfizer-BioNTech and Moderna vaccines demonstrated the highest efficacy, particularly against COVID-19 variants, while Janssen and Sinopharm were comparatively less effective. mRNA vaccines, such as Pfizer-BioNTech and Oxford-AstraZeneca, were associated with more frequent and severe side effects, including soreness, fever, and cardiovascular issues. The review also identified significant gaps in the current scientific literature regarding COVID-19 vaccination issues in Trinidad and Tobago. These gaps highlight the need for comprehensive research to address vaccination challenges, including public health communication, equitable access, and local perceptions of vaccine safety. This analysis provides a foundation for developing targeted strategies to improve vaccine effectiveness in the region.

Covid-19 vaccination coverage and associated factors among older hypertensive patients in Hangzhou, China

BACKGROUND

Vaccination could provide effective protection against coronavirus disease 2019 (COVID-19). This study aims to describe the COVID-19 vaccination coverage and influential factors in Chinese older hypertensive patients.

METHODS

Using a cross-sectional design, participants were randomly selected from the electronic health records system during the pandemic era in Hangzhou, China. Logistic regression models were employed to compute the OR and 95% CI in order to assess the relationships between variables and the extent of COVID-19 vaccination coverage.

RESULTS

As of 3 August 2022, among a sample of 77 970 individuals, 75.11% had completed the full COVID-19 vaccination, while 57.66% had received a booster dose. Disparities in coverage were observed across genders, regions and age groups. Unhealthy lifestyles, cardiovascular disease, cancer, uncontrolled blood pressure, abnormal fasting plasma glucose, dyslipidemia and renal dysfunction were risk factors for COVID-19 vaccination coverage. The coverage rates continuously declined along with the number of risk factors. The ORs for full and booster vaccination in subjects with ≥4 risk factors were 2.55 (2.12∼3.07) and 2.60 (2.16∼3.13), compared to individuals without risk factors.

CONCLUSION

The COVID-19 vaccination program for older hypertensive patients must be strengthened further. Emphasis should be placed on patients who reside in urban areas, have comorbidities or multiple risk factors.

Healthcare workers safety: a cohort study using healthcare utilisation databases on vaccination and vaccine timeliness impact against SARS-CoV-2 infection

Healthcare Workers (HCWs) are at ongoing risk of SARS-CoV-2 infection, potentially contributing to its transmission. This study assessed full vaccination and vaccination timeliness impact on SARS-CoV-2 infections among HCWs in Italy's Marche Region, using Healthcare Utilization Databases. We evaluated vaccination coverage and its associated factors. The cohort comprised 21,118 HCWs aged 18-70 from the region's five Local Health Authorities (LHA), enrolled between February 2020 - May 2021. Factors associated with full vaccination were assessed using multiple logistic regression. The impact of vaccination status, time to vaccination, occupational role, age, gender, and health status on infection risk was analysed with a multiple Cox regression model, adjusting for vaccination coverage velocity, swabbing probability, and monthly intensive care unit admissions rate in each LHA. Of the cohort, 81.2% were fully vaccinated. Factors associated with full vaccination included age, role, LHA, prior infection, and health status. Vaccination reduced infection risk by 77% (95% CI: 70-82). Infection risk was higher among healthcare assistants, nurses/physiotherapists/technicians compared to physicians, among male HCWs, and it decreased as vaccination timeliness increased. Vaccination timeliness is crucial for reducing SARS-CoV-2 infection risk among HCWs, regardless of their characteristics. This underscores the importance of efficiently organizing vaccination administration across different territories and for all HCW categories.

Respiratory Virus Vaccines: Pathways to Recommendations and Enhanced Coverage for At-Risk Populations

While marked differences exist between influenza virus, respiratory syncytial virus (RSV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is substantial overlap in the vulnerability of populations most at risk for severe disease following infection, chief among them being advanced age, multiple comorbidities, and immunocompromise. Vaccination is an established and effective preventative strategy to protect against respiratory viral infections (RVIs), reducing morbidity and mortality, minimizing the potential for long-term complications, and mitigating exacerbation of existing health conditions. Despite the demonstrated benefits of immunization throughout the life course and recommendations by health authorities, coverage rates of at-risk populations against vaccine-preventable diseases remain suboptimal and vary considerably by country and demographic strata. The objective of this supplement's concluding article is to discuss the current barriers to vaccination and strategies to enhance coverage against RVIs among adult at-risk populations. Identified barriers include low awareness of the risks of vaccine-preventable diseases, low perceived benefits of vaccination, and doubts regarding vaccine safety, which together contribute to vaccine hesitancy. Additionally, logistical issues related to vaccine supply, access, and costs present further challenges in achieving optimal coverage. Potential strategies to overcome these barriers and improve uptake include strengthening and harmonizing immunization guidelines and improving respiratory disease surveillance systems to appropriately identify needs and direct resources. Co-administration or use of combination vaccines against multiple viruses may be a viable strategy to enhance coverage by simplifying schedules and improving access, together with future utilization of enhanced vaccine platforms to develop novel vaccines. In addition, vaccination-focused healthcare provider training and consumer education are recommended to address vaccine hesitancy. Reaching vaccination targets and expanding coverage in adult at-risk populations are increasingly achievable with the availability of new and updated vaccination strategies for respiratory viruses, but will require collective efforts across providers, policymakers, scientists, health officials, and the general population.

The Impact of Vaccination on COVID-19, Influenza, and Respiratory Syncytial Virus-Related Outcomes: A Narrative Review

Vaccination represents a core preventive strategy for public health, with interrelated and multifaceted effects across health and socioeconomic domains. Beyond immediate disease prevention, immunization positively influences downstream health outcomes by mitigating complications of preexisting comorbidities and promoting healthy aging. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza virus, and respiratory syncytial virus (RSV) are common respiratory viruses responsible for broad societal cost and substantial morbidity and mortality, particularly among at-risk individuals, including older adults and people with frailty or certain comorbid conditions. In this narrative review, we summarize the overall impact of vaccination for these 3 viruses, focusing on mRNA vaccines, each of which exhibits unique patterns of infection, risk, and transmission dynamics, but collectively represent a target for preventive strategies. Vaccines for COVID-19 (caused by SARS-CoV-2) and influenza are effective against the most severe outcomes, such as hospitalization and death; these vaccines represent the most potent and cost-effective interventions for the protection of population and individual health against COVID-19 and influenza, particularly for older adults and those with comorbid conditions. Based on promising results of efficacy for the prevention of RSV-associated lower respiratory tract disease, the first RSV vaccines were approved in 2023. Immunization strategies should account for various factors leading to poor uptake, including vaccine hesitancy, socioeconomic barriers to access, cultural beliefs, and lack of knowledge of vaccines and disease states. Coadministration of vaccines and combination vaccines, such as multicomponent mRNA vaccines, offer potential advantages in logistics and delivery, thus improving uptake and reducing barriers to adoption of new vaccines. The success of the mRNA vaccine platform was powerfully demonstrated during the COVID-19 pandemic; these and other new approaches show promise as a means to overcome existing challenges in vaccine development and to sustain protection against viral changes over time.A graphical abstract and video abstract is available with this article.

Vaccine adherence and adverse events of the SARS-COV vaccine in patients with inflammatory bowel disease

OBJECTIVE

To assess adherence to and the adverse effects of the SARS-COV vaccine in patients with inflammatory bowel disease (IBD).

PATIENTS AND METHODS

This is an observational, analytical, cross-sectional study. Sociodemographic and clinical data, SARS-COV vaccine data, medications for IBD with use during the vaccination period, and adverse events during the vaccination period were collected. Carried out logistic regressions with robust variance estimation to estimate the odds ratio with the respective 95% confidence intervals (95%CI) to assess the factors associated with non-serious adverse effects following vaccine doses as outcome variables.

RESULTS

194 patients participated, with vaccine compliance of 78.3% for three doses of any vaccine (n=152). Local symptoms and mild systemic symptoms predominated, regardless of the type of vaccine. The first dose of the SARS-COV vaccine with AstraZeneca had a higher percentage of patients with vaccine symptoms. AstraZeneca vaccine increased the chance of non-serious adverse effects in IBD patients by 2.65 times (95% CI: 1.38-5.08; p=0.003), regardless of age, gender, physical activity, excess weight, use of disease-modifying drugs, immunobiological and corticosteroids. CoronaVac vaccine was associated with asymptomatic patients at the first dose and reduced the chance of adverse effects by 0.28 times (OR: 0.284; 95%CI: 0.13-0.62; p=0.002).

CONCLUSION

Local symptoms and mild systemic symptoms predominated, regardless of the type of vaccine. Using CoronaVac in the first dose reduced the chances of adverse effects, while AstraZeneca increased the risk of adverse effects.

The evolution of vaccine hesitancy through the COVID-19 pandemic: A semi-structured interview study on booster and bivalent doses

We sought in-depth understanding on the evolution of factors influencing COVID-19 booster dose and bivalent vaccine hesitancy in a longitudinal semi-structured interview-based qualitative study. Serial interviews were conducted between July 25th and September 1st, 2022 (Phase I: univalent booster dose availability), and between November 21st, 2022 and January 11th, 2023 (Phase II: bivalent vaccine availability). Adults (≥18 years) in Canada who had received an initial primary series and had not received a COVID-19 booster dose were eligible for Phase I, and subsequently invited to participate in Phase II. Twenty-two of twenty-three (96%) participants completed interviews for both phases (45 interviews). Nearly half of participants identified as a woman (n = 11), the median age was 37 years (interquartile range: 32-48), and most participants were employed full-time (n = 12); no participant reported needing to vaccinate (with a primary series) for their workplace. No participant reported having received a COVID-19 booster dose at the time of their interview in Phase II. Three themes relating to the development of hesitancy toward continued vaccination against COVID-19 were identified: 1) effectiveness (frequency concerns; infection despite vaccination); 2) necessity (less threatening, low urgency, alternate protective measures); and 3) information (need for data, contradiction and confusion, lack of trust, decreased motivation). The data from interviews with individuals who had not received a COVID-19 booster dose or bivalent vaccine despite having received a primary series of COVID-19 vaccines highlights actionable targets to address vaccine hesitancy and improve public health literacy.

Vaccination status and disease severity of COVID-19 in different phases of the pandemic

This study aimed to explore the clinical profile and the impact of vaccination status on various health outcomes among COVID-19 patients diagnosed in different phases of the pandemic, during which several variants of concern (VOCs) circulated in South Carolina (SC). The current study included 861,526 adult COVID-19 patients diagnosed between January 2021 and April 2022. We extracted their information about demographic characteristics, vaccination, and clinical outcomes from a statewide electronic health record database. Multiple logistic regression models were used to compare clinical outcomes by vaccination status in different pandemic phases, accounting for key covariates (e.g. historical comorbidities). A reduction in mortality was observed among COVID-19 patients during the whole study period, although there were fluctuations during the Delta and Omicron dominant periods. Compared to non-vaccinated patients, full-vaccinated COVID-19 patients had lower mortality in all dominant variants, including Pre-alpha (adjusted odds ratio [aOR]: 0.33; 95%CI: 0.15-0.72), Alpha (aOR: 0.58; 95%CI: 0.42-0.82), Delta (aOR: 0.28; 95%CI: 0.25-0.31), and Omicron (aOR: 0.29; 95%CI: 0.26-0.33) phases. Regarding hospitalization, full-vaccinated parties showed lower risk of hospitalization than non-vaccinated patients in Delta (aOR: 0.44; 95%CI: 0.41-0.47) and Omicron (aOR: 0.53; 95%CI: 0.50-0.57) dominant periods. The findings demonstrated the protection effect of the COVID-19 vaccines against all VOCs, although some of the full-vaccinated population still have symptoms to varying degrees from COVID-19 disease at different phases of the pandemic.

COVID-19 Vaccination and Transient Increase in CD4/CD8 Cell Counts in People with HIV: Evidence from China

Objectives: Accumulating evidence has confirmed the efficacy and safety of COVID-19 vaccines against SARS-CoV-2 infection. However, the effect of COVID-19 vaccination on immuno-virological parameters in people with HIV (PWH) is uncertain. Methods: A total of 372 PWH treated at Beijing Ditan Hospital were included. Unvaccinated PWH were matched 1:3 with vaccinated PWH using a propensity score matching algorithm. Differences in immuno-virological markers between the matched groups were analyzed. The Wilcoxon signed rank test was used to test for changes in CD4 and CD8 counts and HIV viral load over two months around vaccination. In addition, we investigated the long-term changes in HIV-related markers in different vaccination dose groups and in the entire vaccinated population. Results: Vaccinated PWH had a higher CD4/CD8 ratio (0.64 (0.49, 0.78) vs. 0.80 (0.56, 1.03), p = 0.037) than unvaccinated PWH within a two-month window after the third dose. There were 337 PWH who received COVID-19 vaccination, and 73.9% (n = 249) received three doses of vaccine. We observed a transient increase in CD4 count and CD4/CD8 ratio within a two-month window after vaccination, especially after the second dose (CD4 count: 583.5 (428.5, 706.8) vs. 618.0 (452.0, 744.0), p = 0.018; CD4/CD8 ratio: 0.70 (0.50, 0.91) vs. 0.71 (0.53, 0.96), p < 0.001)) and the third dose (CD4 count: 575.5 (435.5, 717.0) vs. 577.5 (440.8, 754.8), p = 0.001; CD4/CD8 ratio: 0.70 (0.52, 0.93) vs. 0.79 (0.53, 1.00), p < 0.001)). Recent CD4 counts and CD4/CD8 ratios were lower than after COVID-19 but remained higher than before COVID-19 in vaccinated PWH. In addition, COVID-19 vaccination had no negative effect on HIV viral load. Conclusions: A transient increase in CD4 count and CD4/CD8 ratio was observed after COVID-19 vaccination. However, the enhanced cellular immune response induced by vaccination may diminish over time and return to normal levels. There is no adverse effect of vaccination on HIV viral load.

The effect of pre-COVID and post-COVID vaccination on long COVID: A systematic review and meta-analysis

BACKGROUND

Long COVID affects millions of people and results in a substantial decrease in quality of life. Previous primary studies and reviews attempted to study the effect of vaccination against long COVID, but these studies varied in the cut-off time of long COVID. We adhered to the WHO's definition of long COVID and conducted a systematic review and meta-analysis on the effect of pre-COVID and post-COVID vaccination on long COVID.

METHODS

We obtained data from 13 databases up to 18 February 2024, including peer reviewed and preprint studies. Our inclusion criteria were: (1) long COVID definition as 3 months or beyond, (2) comparing long COVID symptoms between vaccinated and unvaccinated groups, (3) subjects received vaccinations either before or after infected with COVID, (4) the number of doses received by participants was specified. We extracted study characteristics and data and computed the summary odds ratio (OR) with the DerSimonian and Laird random effects model. We then performed subgroup analyses based on the main vaccine brand and long COVID assessment method. ROBINS-I framework was used for assessment of risk of bias and the GRADE approach was used for evaluating the certainty of evidence.

FINDINGS

We included data from 25 observational studies (n = 14,128,260) with no randomised controlled trials. One-dose pre-COVID vaccination did not have an effect on long COVID (number of studies = 10, summary OR = 1.01, 95% CI = 0.88-1.15, p-value = 0.896). Two-dose pre-COVID vaccination was associated with a 24% reduced odds of long COVID (number of studies = 15, summary OR = 0.76, 95% CI = 0.65-0.89, p-value = 0.001) and 4 symptoms (fatigue, headache, loss of smell, muscle pain) out of 10 symptoms analysed. The OR of three-dose pre-COVID vaccination against overall long COVID was statistically insignificant but was far away from 1 (number of studies = 3, summary OR = 0.31, 95% CI = 0.05-1.84, p-value = 0.198). One-dose post-COVID vaccination was associated with a 15% reduced odds of long COVID (number of studies = 5, summary OR = 0.85, 95% CI = 0.73-0.98, p-value = 0.024). The OR of two-dose post-COVID vaccination against long COVID was statistically insignificant but was far away from 1 (number of studies = 3, summary OR = 0.63, 95% CI = 0.38-1.03, p-value = 0.066).

INTERPRETATION

Our study suggests that 2-dose pre-COVID vaccination and 1-dose post-COVID vaccination are associated with a lower risk of long COVID. Since long COVID reduces quality of life substantially, vaccination could be a possible measure to maintain quality of life by partially protecting against long COVID.

Effects of Baseline Blood Zinc Levels on the Humoral Immune Response After COVID-19 mRNA Vaccination: A Prospective Study in a Japanese Population

BACKGROUND/OBJECTIVES

Although the protective effects of zinc against COVID-19 are documented, its impact on COVID-19 vaccine immunogenicity remains unknown.

METHODS

We conducted a prospective study involving a cohort of 79 Japanese individuals (aged 21-56 years; comprising three subcohorts) and measured their serum zinc levels pre-vaccination and anti-SARS-CoV-2 IgM/IgG levels pre- and post-vaccination over 4 months.

RESULTS

Serum zinc concentrations ranged between 74-140 and 64-113 μg/dL in male and female individuals, respectively, with one male and 11 female participants exhibiting subclinical zinc deficiency (60-80 μg/dL). Mixed models for antibody titers, accounting for the subcohorts, repeat measurements, and covariates (e.g., vaccine type, sex, age, height, steroid use, medical history, smoking and drinking habits, perceived stress, and sleep disturbances) showed positive effects of zinc on IgM (p = 0.012) and IgG (p = 0.013) in 45 female individuals with 255 observations. However, a similar association was not found in the 34 male participants with 162 observations. This discrepancy may be attributed to one participant being included in the subcohort with frequent repeat measurements (10 repeats in 4 months). COVID-19 mRNA vaccine immunogenicity was enhanced in the participants with high baseline blood zinc levels within the reference range.

CONCLUSIONS

Our findings underscore the relevance of maintaining adequate zinc levels before vaccination, which can be achieved through a balanced diet and healthy lifestyle choices.

The effect of polygenic liability to mental disorders on COVID-19 outcomes in people with depression: the mediating role of anxiety

BACKGROUND

Genetic vulnerability to mental disorders has been associated with coronavirus disease-19 (COVID-19) outcomes. We explored whether polygenic risk scores (PRSs) for several mental disorders predicted poorer clinical and psychological COVID-19 outcomes in people with pre-existing depression.

METHODS

Data from three assessments of the Australian Genetics of Depression Study (N = 4405; 52.2 years ± 14.9; 76.2% females) were analyzed. Outcomes included COVID-19 clinical outcomes (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] infection and long COVID, noting the low incidence of COVID-19 cases in Australia at that time) and COVID-19 psychological outcomes (COVID-related stress and COVID-19 burnout). Predictors included PRS for depression, bipolar disorder, schizophrenia, and anxiety. The associations between these PRSs and the outcomes were assessed with adjusted linear/logistic/multinomial regressions. Mediation (N = 4338) and moderation (N = 3326) analyses were performed to explore the potential influence of anxiety symptoms and resilience on the identified associations between the PRSs and COVID-19 psychological outcomes.

RESULTS

None of the selected PRS predicted SARS-CoV-2 infection or long COVID. In contrast, the depression PRS predicted higher levels of COVID-19 burnout. Anxiety symptoms fully mediated the association between the depression PRS and COVID-19 burnout. Resilience did not moderate this association.

CONCLUSIONS

A higher genetic risk for depression predicted higher COVID-19 burnout and this association was fully mediated by anxiety symptoms. Interventions targeting anxiety symptoms may be effective in mitigating the psychological effects of a pandemic among people with depression.

Factors Predicting COVID-19 Vaccine Effectiveness and Longevity of Humoral Immune Responses

The COVID-19 pandemic, caused by SARS-CoV-2, prompted global efforts to develop vaccines to control the disease. Various vaccines, including mRNA (BNT162b2, mRNA-1273), adenoviral vector (ChAdOx1, Ad26.COV2.S), and inactivated virus platforms (BBIBP-CorV, CoronaVac), elicit high-titer, protective antibodies against the virus, but long-term antibody durability and effectiveness vary. The objective of this study is to elucidate the factors that influence vaccine effectiveness (VE) and the longevity of humoral immune responses to COVID-19 vaccines through a review of the relevant literature, including clinical and real-world studies. Here, we discuss the humoral immune response to different COVID-19 vaccines and identify factors influencing VE and antibody longevity. Despite initial robust immune responses, vaccine-induced immunity wanes over time, particularly with the emergence of variants, such as Delta and Omicron, that exhibit immune escape mechanisms. Additionally, the durability of the humoral immune responses elicited by different vaccine platforms, along with the identification of essential determinants of long-term protection-like pre-existing immunity, booster doses, hybrid immunity, and demographic factors-are critical for protecting against severe COVID-19. Booster vaccinations substantially restore neutralizing antibody levels, especially against immune-evasive variants, while individuals with hybrid immunity have a more durable and potent immune response. Importantly, comorbidities such as diabetes, cardiovascular disease, chronic kidney disease, and cancer significantly reduce the magnitude and longevity of vaccine-induced protection. Immunocompromised individuals, particularly those undergoing chemotherapy and those with hematologic malignancies, have diminished humoral responses and benefit disproportionately from booster vaccinations. Age and sex also influence immune responses, with older adults experiencing accelerated antibody decline and females generally exhibiting stronger humoral responses compared to males. Understanding the variables affecting immune protection is crucial to improving vaccine strategies and predicting VE and protection against COVID-19.

Modeling the interplay between disease spread, behaviors, and disease perception with a data-driven approach

Individuals' perceptions of disease influence their adherence to preventive measures, shaping the dynamics of disease spread. Despite extensive research on the interaction between disease spread, human behaviors, and interventions, few models have incorporated real-world behavioral data on disease perception, limiting their applicability. In this study, we propose an approach to integrate survey data on contact patterns and disease perception into a data-driven compartmental model, by hypothesizing that perceived severity is a determinant of behavioral change. We explore scenarios involving a competition between a COVID-19 wave and a vaccination campaign, where individuals' behaviors vary based on their perceived severity of the disease. Results indicate that behavioral heterogeneities influenced by perceived severity affect epidemic dynamics, in a way depending on the interplay between two contrasting effects. On the one hand, longer adherence to protective measures by groups with high perceived severity provides greater protection to vulnerable individuals, while premature relaxation of behaviors by low perceived severity groups facilitates virus spread. Differences in behavior across different population groups may impact strongly the epidemiological curves, with a transition from a scenario with two successive epidemic peaks to one with only one (higher) peak and overall more numerous severe outcomes and deaths. The specific modeling choices for how perceived severity modulates behavior parameters do not strongly impact the model's outcomes. Moreover, the study of several simplified models indicate that the observed phenomenology depends on the combination of data describing age-stratified contact patterns and of the feedback loop between disease perception and behavior, while it is robust with respect to the lack of precise information on the distribution of perceived severity in the population. Sensitivity analyses confirm the robustness of our findings, emphasizing the consistent impact of behavioral heterogeneities across various scenarios. Our study underscores the importance of integrating risk perception into infectious disease transmission models and gives hints on the type of data that further extensive data collection should target to enhance model accuracy and relevance.

A worldwide look into long COVID-19 management: an END-COVID survey

Background

Long COVID is a heterogeneous clinical syndrome characterised by a variety of reported symptoms and signs. Its clinical management is expected to differ significantly worldwide.

Methods

A survey-based study investigating long COVID-related standard operating procedures (SOPs) has been conducted by the European Respiratory Society (ERS) END-COVID clinical research collaboration with the support of other international societies (ALAT, APSR, CHEST, ESCMID and PATS). A global analysis of the results is provided here, alongside sub-population analysis based on continents, national income levels, type of involved healthcare professional and inclusion or exclusion of paediatric patients.

Findings

1015 healthcare professionals from 110 different countries worldwide participated in this study, the majority of them being respiratory physicians (60.6%). A dedicated long COVID programme was present in 55.4% of the investigated institutions, with hospital admission during the acute infection being the main inclusion criteria to access them. Consistent differences in long COVID-related procedures were identified among centres, mainly regarding the multidisciplinary approach, the availability of telemedicine and psychological support, the type of requested exams and the total amount of visits in the centre.

Interpretation

Long COVID management shows important differences related to geographical areas and national income levels. SOPs were significantly different when centres were managed by a pulmonologist or when paediatric patients were included.

Blood transcriptome profiling reveals distinct gene networks induced by mRNA vaccination against COVID-19

Messenger RNA (mRNA) vaccines represent a new class of vaccines that has been shown to be highly effective during the COVID-19 pandemic and that holds great potential for other preventative and therapeutic applications. While it is known that the transcriptional activity of various genes is altered following mRNA vaccination, identifying and studying gene networks could reveal important scientific insights that might inform future vaccine designs. In this study, we conducted an in-depth weighted gene correlation network analysis of the blood transcriptome before and 24 h after the second and third vaccination with licensed mRNA vaccines against COVID-19 in humans, following a prime vaccination with either mRNA or ChAdOx1 vaccines. Utilizing this unsupervised gene network analysis approach, we identified distinct modular networks of co-varying genes characterized by either an expressional up- or downregulation in response to vaccination. Downregulated networks were associated with cell metabolic processes and regulation of transcription factors, while upregulated networks were associated with myeloid differentiation, antigen presentation, and antiviral, interferon-driven pathways. Within this interferon-associated network, we identified highly connected hub genes such as STAT2 and RIGI and associated upstream transcription factors, potentially playing important regulatory roles in the vaccine-induced immune response. The expression profile of this network significantly correlated with S1-specific IgG levels at the follow-up visit in vaccinated individuals. Those findings could be corroborated in a second, independent cohort of mRNA vaccine recipients. Collectively, results from this modular gene network analysis enhance the understanding of mRNA vaccines from a systems immunology perspective. Influencing specific gene networks could lead to optimized vaccines that elicit augmented vaccine responses.

Social distancing during the COVID-19 pandemic: Potential impact and correlation with asthma

BACKGROUND

Non-pharmaceutical interventions have been implemented globally to control the COVID-19 pandemic and have been shown to alleviate both allergies and respiratory infections. Although mask-wearing is an accepted non-pharmaceutical intervention, the effects of social distancing have not been thoroughly evaluated.

OBJECTIVES

To evaluate the effects of social distancing on asthma trends in Seoul, South Korea.

METHODS

This study included data from the National Health Insurance Service of South Korea, covering approximately 10 million people in Seoul. Daily and monthly data of patients with asthma from 2018 to 2021 were examined, and the degree of social distancing performance was measured using the number of subway users as an index. Pearson's correlation coefficient was used to determine the relationship between the two indices. The change-point detection technique, cross-correlation, and Granger causality method were used to assess the temporal causality between social distancing and asthma.

RESULTS

The number of patients with asthma decreased by 42.4 % from 2019 to 2020, while that of subway users decreased by 26.3 % during this period. Pearson's correlation analysis revealed significant positive correlations. Asthma and subway users showed a significant change in incidence following the implementation of social distancing; subway users showed a causal relationship with patients with asthma.

CONCLUSION

Our results showed that the number of subway users decreased after the implementation of strict social distancing, coinciding with a decrease in the number of patients with asthma. These findings suggest that social distancing measures implemented to control COVID-19 may reduce the incidence and exacerbation of asthma.

Comprehensive analytics of COVID-19 vaccine research: From topic modeling to topic classification

COVID-19 vaccine research has played a vital role in successfully controlling the pandemic, and the research surrounding the coronavirus vaccine is ever-evolving and accruing. These enormous efforts in knowledge production necessitate a structured analysis as secondary research to extract useful insights. In this study, comprehensive analytics was performed to extract these insights, which has moved the boundaries of data analytics in secondary research in the vaccine field by utilizing topic modeling, sentiment analysis, and topic classification based on the abstracts of related publications indexed in Scopus and PubMed. By applying topic modeling to 4803 abstracts filtered by this study criterion, 8 research arenas were identified by merging related topics. The extracted research areas were entitled "Reporting," "Acceptance," "Reaction," "Surveyed Opinions," "Pregnancy," "Titer of Variants," "Categorized Surveys," and "International Approaches." Moreover, the investigation of topics sentiments variations over time led to identifying researchers' attitudes and focus in various years from 2020 to 2022. Finally, a CNN-LSTM classification model was developed to predict the dominant topics and sentiments of new documents based on the 25 pre-determined topics with 75 % accuracy. The findings of this study can be utilized for future research design in this area by quickly grasping the structure of the current research on the COVID-19 vaccine. Through the findings of current research, a classification model was developed to classify the topic of a new article as one of the identified topics. Also, vaccine manufacturing firms will achieve a niche market by having a schema to invest in the gap of fields that have yet to be concentrated in extracted topics.

Controlling the first wave of the COVID-19 pandemic in Malawi: Results from a multi-round study

We investigated behavioral responses to COVID-19 in Malawi, where a first wave of the pandemic occurred between June and August 2020. Contrary to many countries on the African continent, the Government of Malawi did not impose a lockdown or a stay-at-home order in response to the initial spread of SARS-CoV-2. We hypothesized that, in the absence of such requirements to restrict social interactions, individuals would primarily seek to reduce the risk of SARS-CoV-2 transmission during contacts, rather than reduce the extent of their social contacts. We analyzed 4 rounds of a panel survey spanning time periods before, during and after the first wave of the COVID-19 pandemic in Malawi. Five hundred and forty-three participants completed 4 survey interviews between April and November 2020. We found that the likelihood of attending various places and events where individuals work and/or socialize remained largely unchanged during that time. Over the same time frame, however, participants reported adopting on a large scale several behaviors that reduce the transmissibility of SARS-CoV-2 during contacts. The percentage of panel participants who reported practicing physical distancing thus increased from 9.8% to 47.0% in rural areas between April-May 2020 and June-July 2020, and from 11.4% to 59.4% in urban areas. The percentage of respondents who reported wearing a facial mask to prevent the spread of SARS-CoV-2 also increased, reaching 67.7% among rural residents in August-September 2020, and 89.6% among urban residents. The pace at which these behaviors were adopted varied between population groups, with early adopters of mask use more commonly found among more educated office workers, residing in urban areas. The adoption of mask use was also initially slower among women, but later caught up with mask use among men. These findings stress the importance of behavioral changes in containing future SARS-CoV-2 outbreaks in settings where access to vaccination remains low. They also highlight the need for targeted outreach to members of socioeconomic groups in which the adoption of protective behaviors, such as mask use, might be delayed.

Readiness for influenza and COVID-19 vaccination in Germany: a comparative analysis

Introduction

Vaccination readiness refers to psychological motives and beliefs that decisively determine individual and collective vaccination prevention behavior. Readiness to be vaccinated depends on expected individual and social benefits and harms. Differences exist in the perception of the threat of potential influenza vs. COVID-19 infection and its significance for the social environment. The study aimed to compare the 7C components of vaccination readiness for influenza and COVID-19 vaccination in adulthood.

Methods

A total of 317 adults answered the 7C vaccination readiness scale in two vaccination-specific versions (influenza vs. COVID-19) in an online survey from September 2022 to March 2023. Data were analyzed using repeated measures, including analysis of covariance, correlations, and multiple regression.

Results

For COVID-19, there is a higher readiness to be vaccinated compared to influenza regarding complacencyR (ηp  = 0.683), constraintsR (ηp  = 0.684), collective responsibility (ηp  = 0.782), and compliance (ηp  = 0.365). However, confidence (ηp  = 0.161) and conspiracyR (ηp  = 0.256) indicate an enhanced readiness for influenza vaccination (interaction scales × vaccination type: ηp  = 0.602). Individual influenza vaccination recommendations and age do not or only marginally moderate these effects (interaction vaccination type × recommendation: ηp  = 155).

Discussion

The 7C subscales reveal a differentiated pattern of readiness for the two vaccination types. This emphasizes the relevance of the multidimensional structure of the construct of vaccination readiness as well as the relevance of moderating effects of the respective vaccination type on the underlying motives and beliefs. Vaccination attitudes are influenced by cultural and social conditions as well as medical standards of care. Comparing attitudes to different vaccinations in different countries thus represents an important research desideratum in order to understand the concept of vaccination readiness more comprehensively.

To vaccinate or not to vaccinate? Experiences of COVID-19 vaccine uptake among people living with non-communicable diseases in Ghana: A qualitative study

Following the development of a vaccine for COVID-19, the expectation was instantaneous widespread distribution and uptake to halt further spread, severe illness and deaths from the virus. However, studies show very low uptake, especially in resource-poor settings, and little is documented about the drivers of vaccine uptake in populations classified as high-risk. In this study, we explored access and uptake of COVID-19 vaccines among people living with non-communicable diseases (PLWNCDs) in Ghana. A qualitative study using in-depth interviews and focus group discussions was conducted among adults (>18 years) PLWNCDs stratified by sex, age, and type of non-communicable diseases (NCDs) at the community level (non-users of the health service) and health facility levels. Purposive sampling was used to select eligible participants. Topic guides were used to facilitate the face-to-face in-depth interviews and focus group discussions. The interviews and discussions were all digitally audio recorded. All transcripts and field notes were thematically analysed. Overall, 62 participants were recruited for this study. Family members, friends/peers, health workers and media were identified as the main sources of information for COVID-19 vaccines. Several barriers that mediated access to the COVID-19 vaccines in Ghana were reported including mistrust of vaccine efficacy and fears of vaccine side-effects, long distance to and waiting hours at vaccination centres, shortages of vaccines at vaccination centres and non-prioritization of NCD patients for the vaccine. To improve uptake, intensified education and sensitization, house-to-house vaccination, expansion of vaccination centers and increased supply of vaccines were recommended by participants. Compared to studies elsewhere, misinformation and disinformation were not major causes of vaccine hesitancy. If policymakers can improve community-based vaccine delivery, reduce queues and waiting times, prioritize PLWNCDs and other vulnerable groups, and improve sensitization and communication-our findings suggest there will be major improvements in COVID-19 vaccine coverage in Ghana.

Risk of death in England following a positive SARS-CoV-2 test: A retrospective national cohort study (March 2020 to September 2022)

BACKGROUND

We aimed to estimate the relative risk of mortality following a first positive SARS-CoV-2 test during the first, second, and third waves of the COVID-19pandemic in England by age, sex, and vaccination status, taking into account pre-existing health conditions and lifestyle factors.

METHODS

We conducted a retrospective cohort study of all individuals registered with the National Health Service (NHS) in England from 1 March 2020 to September 2022. Data for all individuals were obtained and linked including primary care records, hospital admission episodes, SARS-CoV-2 test results, vaccinations, and death registrations. We fitted Cox Proportional Hazards models with time dependent covariates for confirmed SARS-CoV-2 infection to model the risk of subsequent mortality.

RESULTS

The hazard ratio for death after testing positive for subsequent, compared with those not testing positive, amongst unvaccinated individuals, ranged from 11 to 89 by age and sex, in the first four weeks following a positive test in wave one and reduced to 14 to 50 in wave three. This hazard was further reduced amongst those who had three vaccines to between 1.4 and 7 in wave three.

CONCLUSIONS

This study provides robust estimates of increased mortality risk among those who tested positive over the first three waves of the COVID-19 pandemic in England. The estimates show the impact of various factors affecting the risk of mortality from COVID-19. The results provide the first step towards estimating the magnitude and pattern of mortality displacement due to COVID-19, which is essential to understanding subsequent mortality rates in England.