Safety and effectiveness of SARS-CoV-2 vaccines: A systematic review and meta-analysis

Efficacy, immunogenicity and safety of respiratory syncytial virus prefusion F vaccine: systematic review and meta-analysis

OBJECTIVE

A notable research gap exists in the systematic review and meta-analysis concerning the efficacy, immunogenicity, and safety of the respiratory syncytial virus (RSV) prefusion F vaccine.

METHODS

We conducted a comprehensive search across PubMed, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov to retrieve articles related to the efficacy, immunogenicity, and safety of RSV prefusion F vaccines, published through September 8, 2023. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

A total of 22 randomized controlled trials involving 78,990 participants were included in this systematic review and meta-analysis. The RSV prefusion F vaccine exhibited a vaccine effectiveness of 68% (95% CI: 59-75%) against RSV-associated acute respiratory illness, 70% (95% CI: 60-77%) against medically attended RSV-associated lower respiratory tract illness, and 87% (95% CI: 71-94%) against medically attended severe RSV-associated lower respiratory tract illness. Common reported local adverse reactions following RSV prefusion F vaccination include pain, redness, and swelling at the injection site, and systemic reactions such as fatigue, headache, myalgia, arthralgia, nausea, and chills.

CONCLUSIONS

Our meta-analysis suggests that vaccines using the RSV prefusion F protein as antigen exhibit appears broadly acceptable efficacy, immunogenicity, and safety in the population. In particular, it provides high protective efficiency against severe RSV-associated lower respiratory tract disease.

Understanding the time-driven shifts of vaccine effectiveness against any and severe COVID-19 before and after the surge of Omicron variants within 2.5 years of vaccination: A meta-regression

OBJECTIVES

The COVID-19 pandemic required rapid development of vaccines within a short period of time which did not allow to assess vaccine effectiveness (VE) in the long-term.

METHODS

A computerized literature search was undertaken to identify eligible studies, with no language restrictions, published between 1 December 2020 and 30 June 2023.

RESULTS

Out of a total of 27,597 publications, 761 studies were included. Early VE of 87.2% decreased to 55.1% after 9 months among populations fully immunized not only with mRNA (proxy mRNA) vaccines, and 66.3% decreased to 23.5% in populations immunized exclusively with non-mRNA vaccines. Protection against severe COVID-19 declined to 80.9% for proxy mRNA vaccines and 67.2% for non-mRNA vaccines. Omicron variants significantly diminished VE. Within 6-8 months of receiving a single booster of an mRNA vaccine, VE declined to 14.0% and 67.7% for any and severe COVID-19, respectively. Multiple mRNA booster doses restored protection that declined to 29.5% and 70.6% for any and severe COVID-19, respectively, within 5-7 months.

CONCLUSION

Outcomes of this meta-regression underscore the evolving nature of COVID-19 in response to vaccination, dosing schedules, and emerging variants, and provide crucial insights for public health interventions and vaccination strategies.

Epidemiological characteristics and antibody kinetics of elderly population with booster vaccination following both Omicron BA.5 and XBB waves in China

After the termination of zero-COVID-19 policy, the populace in China has experienced both Omicron BA.5 and XBB waves. Considering the poor antibody responses and severe outcomes observed among the elderly following infection, we conducted a longitudinal investigation to examine the epidemiological characteristics and antibody kinetics among 107 boosted elderly participants following the Omicron BA.5 and XBB waves. We observed that 96 participants (89.7%) were infected with Omicron BA.5, while 59 (55.1%) participants were infected with Omicron XBB. Notably, 52 participants (48.6%) experienced dual infections of both Omicron BA.5 and XBB. The proportion of symptomatic cases appeared to decrease following the XBB wave (18.6%) compared to that after the BA.5 wave (59.3%). Omicron BA.5 breakthrough infection induced lower neutralizing antibody titers against XBB.1.5, BA.2.86, and JN.1, while reinfection with Omicron XBB broadened the antibody responses against all measured Omicron subvariants and may alleviate the wild type-vaccination induced immune imprinting. Boosted vaccination type and comorbidities were the significant factors associated with antibody responses. Updated vaccines based on emerging severe acute respiratory syndrome coronavirus 2 variants are needed to control the Coronavirus Disease 2019 pandemic in the elderly.

Rare COVID-19 vaccine side effects got lost in the shuffle. Primary cutaneous lymphomas following COVID-19 vaccination: a systematic review

Introduction

COVID-19 vaccines are generally safe and effective; however, they are associated with various vaccine-induced cutaneous side effects. Several reported cases of primary cutaneous lymphomas (CLs) following the COVID-19 vaccination have raised concerns about a possible association. This systematic review aims to investigate and elucidate the potential link between CLs and SARS-CoV-2 vaccines.

Methods

We performed a systematic literature search on PubMed, EBSCO and Scopus from January 01, 2019, to March 01, 2023, and analyzed studies based on determined eligibility criteria. The systematic review was performed based on the PRISMA protocol.

Results

A total of 12 articles (encompassing 24 patients) were included in this analysis. The majority of CLs were indolent cutaneous T-cell lymphomas (CTCLs) (66,7%; 16/24), with Lymphomatoid papulosis (LyP) being the most common type (33,3%; 8/24). Most patients (79,2%; 19/24) developed lesions after receiving the COVID-19 mRNA-based vaccines, and predominantly after the first immunization dose (54,2%; 13/24). The presented CLs cases exhibited a tendency to exacerbate following subsequent COVID-19 vaccinations. Nevertheless, CLs were characterized by a favorable course, leading to remission in most cases.

Conclusion

The available literature suggests an association between the occurrence and exacerbation of CLs with immune stimulation following COVID-19 vaccination. We hypothesize that post-vaccine CLs result from an interplay between cytokines and disrupted signaling pathways triggered by vaccine components, concurrently playing a pivotal role in the pathomechanism of CLs. However, establishing a definitive causal relationship between these events is currently challenging, primarily due to the relatively low rate of reported post-vaccine CLs. Nonetheless, these cases should not be disregarded, and patients with a history of lymphoproliferative disorders require post-COVID-19 vaccination monitoring to control the disease's course.Systematic review registrationwww.researchregistry.com, identifier [1723].

A Systematic Review of COVID-19 Vaccine-Induced Takotsubo Cardiomyopathy: A 2023 Update

Takotsubo cardiomyopathy (TCM) is a life-threatening transient left ventricular dysfunction triggered by either physical or emotional stressors. Concerns have been raised on reports of TCM after the coronavirus disease 2019 (COVID-19) vaccine. Our study provides comprehensive detail on COVID-19 vaccine-induced TCM. We conducted a systemic literature search using major databases, including PubMed, EMBASE, and Google Scholar up to November 2023, to identify cases of COVID-19 vaccine-induced TCM using the MeSH terms and keywords "covid-19 vaccines" and "takotsubo cardiomyopathy". We identified 15 case reports, including 16 patients with COVID-19 vaccine-induced TCM. The mean age was 55.81 ± 19.13 years, and 75% of the patients were female. The most common presentation was chest pain (62.5%), and the average time to first symptom onset was 3.12 ± 2.24 days. COVID-19 vaccine-induced TCM was reported in 43.75% of patients receiving the first and second dose each, and 87% of patients had messenger ribonucleic acid (mRNA) COVID-19 vaccine (Pfizer, Moderna). The elevated level of cardiac troponins was found in all the patients with a left ventricular ejection fraction (LVEF) of <50% in 15 patients, and T-wave inversion (50%) was the most common electrocardiographic finding. The mean length of the hospital stay was 7.27 ± 3.95 days, and 87% of patients were discharged. COVID-19 vaccine-induced TCM is a rare but life-threatening complication. TCM should be included in the differential diagnosis of chest pain or dyspnea in patients recently receiving the COVID-19 vaccine.

Comparison of Immunogenicity of Alum and MF59-Like Adjuvant Inactivated SARS-CoV-2 Vaccines Against SARS-CoV-2 Variants in Elderly Mice

The constant emergence of variants of concern (VOCs) challenges the effectiveness of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines over time. This is most concerning in clinically vulnerable groups, such as older adults. This study aimed to determine whether the novel adjuvant MF59-like adjuvant can improve cross-immunity against VOCs in aged animals. We compared the humoral and cellular immune responses of Alum and MF59-like adjuvant-formulated inactivated coronavirus disease 2019 (COVID-19) vaccines against prototype and SARS-CoV-2 variants in 18-month-old mice. Our results showed that two doses of the MF59-like adjuvant inactivated vaccines induced more robust binding and pseudo-neutralizing antibodies (Nabs) against the SARS-CoV-2 prototype and VOCs compared to the Alum-adjuvant and reduced Omicron variant escapes from Nabs in aged mice. The humoral immune responses of inactivated vaccines were much lower against VOCs than the prototype with or without adjuvants; however, T cell responses against VOCs were not affected. In addition, Alum and MF59-like adjuvanted vaccines induced Th1-biased immune responses with increased interferon-gamma and interleukin (IL)-2 secreting cells, and hardly detectable IL-4 and IL-5. Furthermore, the MF59-like adjuvant vaccine produced 1.9-2.0 times higher cross-reactive T cell responses against the SARS-CoV-2 prototype and VOCs than the Alum adjuvant. Therefore, our data have important implications for vaccine adjuvant strategies against SARS-CoV-2 VOCs in older adults.

Effectiveness and Safety of COVID-19 Vaccinations: An Umbrella Meta-Analysis

Objectives: This umbrella meta-analysis aims to provide comprehensive and synthesized evidence regarding the effectiveness and safety of COVID-19 vaccinations based on current studies. Methods: Studies from the Cochrane Library, PubMed, and EMBASE, published before 10 December 2021, were included in the analysis. The pooled results of effectiveness and safety were estimated and shown in forest plots. Results: We included nineteen studies (fifteen studies regarding safety and nine regarding effectiveness) in the analysis. The mRNA vaccines, adenovirus vector vaccines, subunit vaccines, and inactivated vaccines were found to be effective; however, mRNA vaccines, adenovirus vector vaccines and subunit vaccines were associated with local adverse events and systemic events when compared with inactivated vaccines. Conclusion: Our study suggested that till date, COVID-19 vaccination is still a preferred pharmaceutical way to control the widespread pandemic. However, all reported adverse events should be revisited to provide further evidence for mass vaccinations.

[Reasons of Individuals 60 Years and Older in Germany for not Getting Vaccinated against Covid-19]

PURPOSE

To identify the reasons of individuals aged 60 years and older in Germany for not getting vaccinated against Covid-19.

METHODS

Data for this study were collected in July/August 2021 from "Kommunikation der Corona-Schutzimpfung in Deutschland" (CoSiD)", a representative survey of the general adult population in Germany. The focus was on individuals aged 60 years and older in our current study (n=1,281 individuals).

RESULTS

Approximately 92% of individuals 60 years and older were already vaccinated against Covid-19. Among the older unvaccinated, nearly 60% were opposed to vaccination. Major reasons among older (and also younger) unvaccinated persons for "rather not getting vaccinated"/"definitely not" wanting to be vaccinated against Covid-19 were: (1) too little research on the vaccines or too short a time of research (roughly half of the individuals) and (2 and 3) no confidence/general skepticism or because of side effects (in each case, just over a quarter of the group surveyed).

CONCLUSION

To increase the vaccination rate, these three arguments must be countered, for instance, during conversations in the context of medical care.

The Infection Profile and Survival of Children and Adolescents With COVID-19 Undergoing Cancer Treatment: A Cohort Study

OBJECTIVE

The objective of this study was to evaluate the clinical evolution of coronavirus disease 2019 (COVID-19) in children and adolescents with cancer.

METHODS

Cohort involving patients undergoing cancer treatment, 19 years old and under, with the diagnosis of COVID-19 by real-time polymerase chain reaction, in a reference hospital, between March 2020 and November 2021. Data were collected from medical records and interviews with patients and/or guardians. The primary outcomes studied were severe/critical COVID-19 presentation, deaths from any cause and overall survival. The Cox proportional hazards multivariate regression analysis was performed to determine the risk of death.

RESULTS

Sixty-two participants were included, most (67.7%) were male, with a median age of 6.8 years. Severe/critical forms of COVID-19, observed in 24.2%, seemed to indicate that the pediatric population undergoing cancer treatment has a higher morbidity rate than the general pediatric population (8-9.2%). During follow-up (4.5-18 months), 20 patients (32.3%) completed their cancer treatment and 18 died (29%)-6 during hospitalization and 12 after discharge. In total 61.1% of deaths occurred within 63 days of a detectable real-time polymerase chain reaction. Patients with a higher risk of death presented with severe/critical COVID-19 [adjusted hazard risk (aHR): 8.51; 95% confidence interval (CI): 2.91-24.80; P < 0.00] solid tumors (aHR: 3.99; 95% CI: 1.43-11.12; P = 0.008) and diarrhea as a symptom of COVID-19 (aHR: 3.9; 95% CI: 1.23-12.73; P = 0.021).

CONCLUSIONS

These findings support the impact that severe acute respiratory syndrome-associated coronavirus 2 infection has on the population of children and adolescents with cancer, not only regarding immediate severity but also in their survival rate. Further studies evaluating long-term outcomes of COVID-19 in children and adolescents with cancer should be encouraged.

A Meta-Analysis To Ascertain the Effectiveness of COVID-19 Vaccines on Clinical Outcomes in Patients With COVID-19 Infection in North America

The challenges in controlling the pandemic have been exacerbated by the disease's morbidity and the emergence of additional COVID-19 variants. The use of emergency vaccines to circumvent these challenges has sparked mixed opinions on their effectiveness. Therefore, we conducted a meta-analysis to assess the efficacy of COVID-19 vaccines on clinical outcomes such as incidence, hospitalization, and ventilation rates in both vaccinated and unvaccinated patients. PubMed, Google Scholar, and Cochrane Central Register of Clinical Trials were searched on April 21, 2022, to extract published articles comparing vaccinated COVID-19 patients versus unvaccinated COVID-19 patients and their clinical outcomes. The clinical outcomes studied were incidence rate, intensive care unit (ICU) admission, mechanical ventilation, and hospitalization rates. The analysis was performed with Review Manager (RevMan) software. Random-effect models were used to calculate pooled odds ratio and corresponding 95% confidence interval (CI). In our meta-analysis, we have identified a total of 250 published findings, encompassing 15 studies that involved a cumulative count of 24,164,227 individuals diagnosed with COVID-19. Being unvaccinated had a significant association with severe clinical outcomes in patients infected with COVID-19. Unvaccinated individuals were 2.36 times more likely to be infected, with a 95% CI ranging from 1.13 to 4.94 (p = 0.02). Unvaccinated subjects with COVID-19 infection were 6.93 times more likely to be admitted to the ICU than their vaccinated counterparts, with a 95% CI ranging from 3.57 to 13.46 (p < 0.0001). The hospitalization rate was 3.37 higher among the unvaccinated compared to those vaccinated, with a 95% CI ranging from 1.92 to 5.93 (p < 0.0001). In addition, patients with COVID-19 infection who are unvaccinated were 6.44 times more likely to be mechanically ventilated than those vaccinated, with a 95% CI ranging from 3.13 to 13.23 (p < 0.0001). Overall, our study revealed that vaccination against COVID-19 disease is beneficial and effective in mitigating the spread of the infection and associated clinical outcomes. However, more awareness and proper education must be made to increase vaccine acceptance. We, therefore, recommend and urge all stakeholders involved in COVID-19 prevention, management, and control to strengthen awareness and educate the people on the effectiveness of COVID-19 vaccination.

Safety and immunogenicity of heterologous boosting with orally aerosolised or intramuscular Ad5-nCoV vaccine and homologous boosting with inactivated vaccines (BBIBP-CorV or CoronaVac) in children and adolescents: a randomised, open-label, parallel-controlled, non-inferiority, single-centre study

BACKGROUND

Heterologous booster immunisation with orally administered aerosolised Ad5-nCoV vaccine (AAd5) has been shown to be safe and highly immunogenic in adults. Here, we aimed to assess the safety and immunogenicity of heterologous booster immunisation with orally administered AAd5 in children and adolescents aged 6-17 years who had received two doses of inactivated vaccine (BBIBP-CorV or CoronaVac).

METHODS

We did a randomised, open-label, parallel-controlled, non-inferiority study to assess the safety and immunogenicity of heterologous booster immunisation with AAd5 (0·1 mL) or intramuscular Ad5-nCoV vaccine (IMAd5; 0·3 mL) and homologous booster immunisation with inactivated vaccine (BBIBP-CorV or CoronaVac; 0·5 mL) in children (aged 6-12 years) and adolescents (aged 13-17 years) who had received two doses of inactivated vaccine at least 3 months earlier in Hunan, China. Children and adolescents who were previously immunised with two-dose BBIBP-CorV or CoronaVac were recruited for eligibility screening at least 3 months after the second dose. A stratified block method was used for randomisation, and participants were stratified by age and randomly assigned (3:1:1) to receive AAd5, IMAd5, or inactivated vaccine. The study staff and participants were not masked to treatment allocation. Laboratory and statistical staff were masked during the study. In this interim analysis, adverse events within 14 days and geometric mean titre (GMT) of serum neutralising antibodies on day 28 after the booster vaccination, based on the per-protocol population, were used as the primary outcomes. The analysis of non-inferiority was based on comparison using a one-sided 97·5% CI with a non-inferiority margin of 0·67. This study was registered at ClinicalTrials.gov, NCT05330871, and is ongoing.

FINDINGS

Between April 17 and May 28, 2022, 436 participants were screened and 360 were enrolled: 220 received AAd5, 70 received IMAd5, and 70 received inactivated vaccine. Within 14 days after booster vaccination, vaccine-related adverse reactions were reported: 35 adverse events (in 13 [12%] of 110 children and 22 [20%] of 110 adolescents) in 220 individuals in the AAd5 group, 35 (in 18 [51%] of 35 children and 17 [49%] of 35 adolescents) in 70 individuals in the IMAd5 group, and 13 (in five [14%] of 35 children and eight [23%] of 35 adolescents) in 70 individuals in the inactivated vaccine group. Solicited adverse reactions were also reported: 34 (13 [12%] of 110 children and 21 [10%] of 110 adolescents) in 220 individuals in the AAd5 group, 34 (17 [49%] of 35 children and 17 [49%] of 35 adolescents) in 70 individuals in the IMAd5 group, and 12 (five [14%] of 35 children and seven [20%] of 35 adolescents) in 70 individuals in the inactivated vaccine group. The GMTs of neutralising antibodies against ancestral SARS-CoV-2 Wuhan-Hu-1 (Pango lineage B) in the AAd5 group were significantly higher than the GMTs in the inactivated vaccine group (adjusted GMT ratio 10·2 [95% CI 8·0-13·1]; p<0·0001).

INTERPRETATION

Our study shows that a heterologous booster with AAd5 is safe and highly immunogenic against ancestral SARS-CoV-2 Wuhan-Hu-1 in children and adolescents.

FUNDING

National Key R&D Program of China.

Self-Boosting Vaccination Based on Pulsatile Antigen Release from Core-Shell Microparticles

Vaccination is among the most effective ways to prevent infectious diseases. Subunit vaccines are safe but usually require multiple booster shots, which may lead to immunity loss and economic consume. In this study, a self-boosting vaccine is developed based on the pulsatile release of antigen from the core-shell microparticle after single-injection immunization. Self-healing technology applied to form an "antigen core" can avoid organic solvents from destroying the spatial structure of the antigen. The "antigen shell" is built-up by self-assemble of the antigen with the opposite charged polypeptide. Primary immunization occurs with the self-assembled film disintegration, and the booster comes with the microparticle degradation. The changing of antigen-specific antibodies after immunization with the core-shell microparticle vaccine is consistent with that caused by the two shots of immunization. The immune effect and safety evaluation results support the translational potential of this self-boosting core-shell microparticle vaccine.

Diagnosis of Acute Myocarditis Following mRNA Vaccines against SARS-CoV-2: A Methodological Review

The occurrence of acute myocarditis following the administration of mRNA vaccines against SARS-CoV-2 remains relatively rare, and it is associated with a very low mortality rate. The incidence varied by vaccine type, sex, and age and after the first, second, or third vaccination dose. However, the diagnosis of this condition often remains challenging. To further elucidate the relationship between myocarditis and SARS-CoV-2 mRNA vaccines, starting with two cases observed at the Cardiology Unit of the West Vicenza General Hospital located in the Veneto Region, which was among the first Italian areas hit by the COVID-19 pandemic, we performed a review of the available literature to highlight the clinical and diagnostic elements that could contribute to suspicion of myocarditis as an adverse event of SARS-CoV-2 immunization.

From Immunogen to COVID-19 vaccines: Prospects for the post-pandemic era

The COVID-19 pandemic has affected millions of people and posed an unprecedented burden on healthcare systems and economies worldwide since the outbreak of the COVID-19. A considerable number of nations have investigated COVID-19 and proposed a series of prevention and treatment strategies thus far. The pandemic prevention strategies implemented in China have suggested that the spread of COVID-19 can be effectively reduced by restricting large-scale gathering, developing community-scale nucleic acid testing, and conducting epidemiological investigations, whereas sporadic cases have always been identified in numerous places. Currently, there is still no decisive therapy for COVID-19 or related complications. The development of COVID-19 vaccines has raised the hope for mitigating this pandemic based on the intercross immunity induced by COVID-19. Thus far, several types of COVID-19 vaccines have been developed and released to into financial markets. From the perspective of vaccine use in globe, COVID-19 vaccines are beneficial to mitigate the pandemic, whereas the relative adverse events have been reported progressively. This is a review about the development, challenges and prospects of COVID-19 vaccines, and it can provide more insights into all aspects of the vaccines.

Autonomic Function Recovery and Physical Activity Levels in Post-COVID-19 Young Adults after Immunization: An Observational Follow-Up Case-Control Study

Coronavirus disease 2019 (COVID-19) has detrimental multi-system consequences. Symptoms may appear during the acute phase of infection, but the literature on long-term recovery of young adults after mild to moderate infection is lacking. Heart rate variability (HRV) allows for the observation of autonomic nervous system (ANS) modulation post-SARS-CoV-2 infection. Since physical activity (PA) can help improve ANS modulation, investigating factors that can influence HRV outcomes after COVID-19 is essential to advancements in care and intervention strategies. Clinicians may use this research to aid in the development of non-medication interventions. At baseline, 18 control (CT) and 20 post-COVID-19 (PCOV) participants were observed where general anamnesis was performed, followed by HRV and PA assessment. Thus, 10 CT and 7 PCOV subjects returned for follow-up (FU) evaluation 6 weeks after complete immunization (two doses) and assessments were repeated. Over the follow-up period, a decrease in sympathetic (SNS) activity (mean heart rate: p = 0.0024, CI = -24.67--3.26; SNS index: p = 0.0068, CI = -2.50--0.32) and increase in parasympathetic (PNS) activity (mean RR: p = 0.0097, CI = 33.72-225.51; PNS index: p = 0.0091, CI = -0.20-1.47) were observed. At follow-up, HRV was not different between groups (p > 0.05). Additionally, no differences were observed in PA between moments and groups. This study provides evidence of ANS recovery after SARS-CoV-2 insult in young adults over a follow-up period, independent of changes in PA.

Cardiovascular safety of COVID-19 vaccines in real-world studies: a systematic review and meta-analysis

OBJECTIVES

To evaluate the cardiovascular safety of COVID-19 vaccines in the real world.

METHODS

Studies reported on any COVID-19 vaccine-related cardiovascular events in the population aged ≥12 years between 1 January 2020 and 15 June 2022 were included.

RESULTS

A total of 42 studies were included in this meta-analysis. Myocarditis risk was mainly seen after the second (risk ratio [RR], 2.09; 95% confidence interval [CI]: 1.59-2.58) and third (RR, 2.02; 95% CI: 1.04-2.91) dose. A total of 5 vaccines were analyzed, among which mRNA-1273 (RR, 3.13; 95% CI: 2.11-4.14) and BNT162b2 (RR, 1.57; 95% CI: 1.30-1.85) vaccines were associated with myocarditis risk. No significant increase in risk of myocardial infarction (RR, 0.96) or arrhythmia (RR, 0.98) events was observed following vaccination. The risk of cardiovascular events (myocarditis, RR, 8.53; myocardial infarction, RR, 2.59; arrhythmia, RR, 4.47) after SARS-CoV-2 infection was much higher than after vaccination.

CONCLUSIONS

The risk of myocarditis was observed after COVID-19 vaccination, but it was much lower than that following the SARS-CoV-2 infection. No significant increased risk of myocardial infarction or arrhythmia was found after COVID-19 vaccination.

MicroRNAs in T Cell-Immunotherapy

MicroRNAs (miRNAs) act as master regulators of gene expression in homeostasis and disease. Despite the rapidly growing body of evidence on the theranostic potential of restoring miRNA levels in pre-clinical models, the translation into clinics remains limited. Here, we review the current knowledge of miRNAs as T-cell targeting immunotherapeutic tools, and we offer an overview of the recent advances in miRNA delivery strategies, clinical trials and future perspectives in RNA interference technologies.

COVID-19 vaccination challenges: A mini-review

The emergence of SARS-CoV-2 has led to the infection of many people across the globe, over six million deaths, and has placed an unprecedented burden on public health worldwide. The pandemic has led to the high-speed development and production of vaccines against the COVID-19, as vaccines can end the pandemic. At the beginning of the program, vaccinations were initially targeted only at high-risk groups, such as the elderly, those with comorbidities, or healthcare workers. Although most of the mentioned populations have received the two recommended doses, limited resources have left many authorities with an effective vaccine undersupply. Therefore, policies have been implemented to manage the available doses of the vaccines more efficiently. As there is no universally agreed consensus on this topic, we discuss the different recommendations and guidelines regarding the time interval between the two vaccine doses and explain the different scenarios for applying the two doses.

Booster COVID-19 vaccination against the SARS-CoV-2 Omicron variant: A systematic review

There is a wealth of data suggesting that the effectiveness of existing vaccines against the Omicron variant, the most mutated SARS-CoV-2 variant to date, has been substantially reduced if only primary vaccination is administered. Therefore, the effectiveness of booster vaccination against the Omicron variant has become a topic of current interest. We conducted a comprehensive search in PubMed, Embase, and the Cochrane Library to collect various pseudovirus neutralization tests or live virus neutralization tests for the Omicron variant, with serum specimens from booster vaccinees. We extracted neutralization titers for the Omicron variant, the original strain, and the other variants before and after booster vaccination, and then manually calculated the fold increase or decrease in neutralization titers for the Omicron variant relative to the other variants, and the fold increase in neutralization titers for the Omicron variant after booster vaccination compared with that before booster vaccination. In the two-dose vaccination regimen, the neutralization titers against the Omicron variant decreased substantially compared to the original strain and other variants. However, after booster vaccination, both homologous and heterologous booster vaccination, the neutralization of serum antibodies against the Omicron variant was significantly improved, although still lower than that of the original strain and other variants. The booster vaccination program based on existing vaccines can produce broad but incomplete immunity against the Omicron variant.

Risk factors affecting COVID-19 vaccine effectiveness identified from 290 cross-country observational studies until February 2022: a meta-analysis and meta-regression

BACKGROUND

Observational studies made it possible to assess the impact of risk factors on the long-term effectiveness of mRNA and adenoviral vector (AdV) vaccines against COVID-19.

METHODS

A computerized literature search was undertaken using the MEDLINE, EMBASE, and MedRxiv databases to identify eligible studies, with no language restrictions, published up to 28 February 2022. Eligible were observational studies assessing vaccine effectiveness (VE) by disease severity with reference groups of unvaccinated participants or participants immunized with one, two, or three vaccine doses. Our study was carried out in compliance with the PRISMA and MOOSE guidelines. The risk of study bias was identified using the Newcastle-Ottawa Quality Assessment Scale. The GRADE guidelines were applied to assess the strength of evidence for the primary outcome. The synthesis was conducted using a meta-analysis and meta-regression.

RESULTS

Out of a total of 14,155 publications, 290 studies were included. Early VE of full vaccination against COVID-19 of any symptomatology and severity decreased from 96% (95% CI, 95-96%) for mRNA and from 86% (95% CI, 83-89%) for AdV vaccines to 67% for both vaccine types in the last 2 months of 2021. A similar 1-year decline from 98 to 86% was found for severe COVID-19 after full immunization with mRNA, but not with AdV vaccines providing persistent 82-87% effectiveness. Variant-reduced VE was only associated with Omicron regardless of disease severity, vaccine type, or vaccination completeness. The level of protection was reduced in participants aged >65 years, with a comorbidity or those in long-term care or residential homes independently of the number of doses received. The booster effect of the third mRNA dose was unclear because incompletely restored effectiveness, regardless of disease severity, declined within a short-term interval of 4 months.

CONCLUSIONS

Full vaccination provided an early high, yet waning level of protection against COVID-19 of any severity with a strong impact on the high-risk population. Moreover, the potential risk of new antigenically distinct variants should not be underestimated, and any future immunization strategy should include variant-updated vaccines.

The immunogenicity of an inactivated vaccine against SARS-CoV-2 in healthy individuals: A systematic review and meta-analysis

OBJECTIVE

Inactivated (killed) vaccines against COVID-19 have been widely used for the control of the pandemic condition. We performed a systematic and meta-analysis review of randomized, double-blind, placebo-controlled trials of the immunogenicity of inactivated vaccines against SARS-CoV-2 in healthy individuals.

METHODS

In the present study, all research and evidence were extracted from the available online databases. Two researchers randomly evaluated the assessment of the research sensitivity. Finally, after quality assessment and regarding the specific inclusion and exclusion criteria, the eligible articles were entered for meta-analysis. The heterogeneity between the results of the studies was measured using test statistics (Cochran's Q) and the I² index. The forest plots illustrated the point and pooled estimates with 95% confidence intervals (crossed lines). All statistical analyses were performed using Comprehensive meta-Analysis V.2 software.

RESULTS

This meta-analysis included six primary studies investigating the immunogenicity of inactivated vaccines against SARS-CoV-2 in healthy individuals. According to the pooled prevalence (95% confidence interval), neutralizing antibody responses 28 days after receiving the second dose regarding different ages and micrograms per dose was 95.50% (CI: 93.2-97.1%). Our results showed that antibody levels were higher in the 6 μg group than in other groups. 98.3% (CI: 94.2-99.5%).

CONCLUSION

Since the rapid development of vaccinations has sparked widespread public anxiety regarding vaccine efficacy. Governments and unvaccinated individuals, particularly those with vaccination reluctance, will be interested in and benefit from the findings of this systematic study.

Polyethylene glycol (PEG): The nature, immunogenicity, and role in the hypersensitivity of PEGylated products

Polyethylene glycol (PEG) is a versatile polymer that is widely used as an additive in foods and cosmetics, and as a carrier in PEGylated therapeutics. Even though PEG is thought to be less immunogenic, or perhaps even non-immunogenic, with a variety of physicochemical properties, there is mounting evidence that PEG causes immunogenic responses when conjugated with other materials such as proteins and nanocarriers. Under these conditions, PEG with other materials can result in the production of anti-PEG antibodies after administration. The antibodies that are induced seem to have a deleterious impact on the therapeutic efficacy of subsequently administered PEGylated formulations. In addition, hypersensitivity to PEGylated formulations could be a significant barrier to the utility of PEGylated products. Several reports have linked the presence of anti-PEG antibodies to incidences of complement activation-related pseudoallergy (CARPA) following the administration of PEGylated formulations. The use of COVID-19 mRNA vaccines, which are composed mainly of PEGylated lipid nanoparticles (LNPs), has recently gained wide acceptance, although many cases of post-vaccination hypersensitivity have been documented. Therefore, our review focuses not only on the importance of PEGs and its great role in improving the therapeutic efficacy of various medications, but also on the hypersensitivity reactions attributed to the use of PEGylated products that include PEG-based mRNA COVID-19 vaccines.

Comparison of Four Real-Time Polymerase Chain Reaction Assays for the Detection of SARS-CoV-2 in Respiratory Samples from Tunja, Boyacá, Colombia

Coronavirus disease (COVID-19) is an infectious disease caused by SARS-CoV-2. In Colombia, many commercial methods are now available to perform the RT-qPCR assays, and laboratories must evaluate their diagnostic accuracy to ensure reliable results for patients suspected of being positive for COVID-19. The purpose of this study was to compare four commercial RT-qPCR assays with respect to their ability to detect the SARS-CoV2 virus from nasopharyngeal swab samples referred to Laboratorio Carvajal IPS, SAS in Tunja, Boyacá, Colombia. We utilized 152 respiratory tract samples (Nasopharyngeal Swabs) from patients suspected of having SARS-CoV-2. The diagnostic accuracy of GeneFinder^TM COVID-19 Plus RealAmp (In Vitro Diagnostics) (GF-TM), One-Step Real-Time RT-PCR (Vitro Master Diagnostica) (O-S RT-qPCR), and the Berlin modified protocol (BM) were assessed using the gold-standard Berlin protocol (Berlin Charité Probe One-Step RT-qPCR Kit, New England Biolabs) (BR) as a reference. Operational characteristics were estimated in terms of sensitivity, specificity, agreement, and predictive values. Using the gold-standard BR as a reference, the sensitivity/specificity of the diagnostic tests was found to be 100%/92.7% for GF-TM, 92.75%/67.47% for O-S RT-qPCR, and 100%/96.39% for the BM protocol. Using BR as a reference, the sensitivity/specificity for the diagnostic tests were found to be 100%/92.7% for the GF-TM assay, 92.72%/67.47% for the O-S RT-qPCR, and 100%/96.39% for BM. Relative to the BR reference protocol, the GF-TM and BM RT-PCR assays obtained similar results (k = 0.92 and k = 0.96, respectively), whereas the results obtained by O-S-RT-qPCR were only moderately similar. We conclude that the GF-TM and BM protocols offer the best sensitivity and specificity, with similar results in comparison to the gold-standard BR protocol. We recommend evaluating the diagnostic accuracy of the OS-RT-qPCR protocol in future studies with a larger number of samples.

Efficacy and safety of COVID-19 vaccines: A network meta-analysis

OBJECTIVE

Several vaccines showed a good safety profile and significant efficacy against COVID-19. Moreover, in the absence of direct head to head comparison between COVID-19 vaccines, a network meta-analysis that indirectly compares between them is needed.

METHODS

Databases PubMed, CENTRAL, medRxiv, and clinicaltrials.gov were searched. Studies were included if they were placebo-controlled clinical trials and reported the safety profile and/or effectiveness of COVID-19 vaccines. The quality of the included studies was assessed using the Revised Cochrane risk-of-bias tool for randomized trials and the Revised Cochrane risk-of-bias tool for nonrandomized trials.

RESULTS

Forty-nine clinical trials that included 421,173 participants and assessed 28 vaccines were included in this network meta-analysis. The network meta-analysis showed that Pfizer is the most effective in preventing COVID-19 infection whereas the Sputnik Vaccine was the most effective in preventing severe COVID-19 infection. In terms of the local and systemic side, the Sinopharm and V-01 vaccines were the safest.

CONCLUSION

We found that almost all of the vaccines included in this study crossed the threshold of 50% efficacy. However, some of them did not reach the previously mentioned threshold against the B.1.351 variant while the remainder have not yet investigated vaccine efficacy against this variant. Since each vaccine has its own strong and weak points, we strongly advocate continued vaccination efforts in individualized manner that recommend the best vaccine for each group in the community which is abundantly required to save lives and to avert the emergence of future variants.

Disproportionality analysis of adverse neurological and psychiatric reactions with the ChAdOx1 (Oxford-AstraZeneca) and BNT162b2 (Pfizer-BioNTech) COVID-19 vaccines in the United Kingdom

BACKGROUND

Information on neurological and psychiatric adverse events following immunization (AEFIs) with COVID-19 vaccines is limited.

RESEARCH DESIGN & METHODS

We examined and compared neurological and psychiatric AEFIS reports related to BNT162b2 (Pfizer-BioNTech) and ChAdOx1 (Oxford-AstraZeneca) COVID-19 vaccines and recorded in the United Kingdom Medicines and Healthcare products Regulatory Agency between 9/DEC/2020 and 30/JUN/2021.

RESULTS

As of 30/JUN/2021, 53.2 million doses of ChAdOx1 and 46.1 million doses of BNT162b2 had been administered. The most frequently reported AEFI was headache with 1,686 and 575 cases per million doses of ChAdOx1 and BNT162b2, respectively. AEFIs more frequently reported after CHAdOx1 compared with BNT162b2 vaccination were Guillain-Barré syndrome (OR, 95% CI= 2.53, 1.82-3.51), freezing (6.66, 3.12-14.22), cluster headache (1.53, 1.28-1.84), migraine (1.23,1.17-1.30), postural dizziness (1.24,1.13-1.37), tremor (2.86, 2.68-3.05), headache (1.40, 1.38-1.43), paresthesia (1.11, 1.06-1.16), delirium (1.85, 1.45-2.36), hallucination (2.20, 1.82-2.66), poor quality sleep (1.53, 1.26-1.85), and nervousness (1.54, 1.26-1.89) Reactions less frequently reported with ChAdOx1 than with BNT162b2 were Bell's palsy (0.47, 0.41-0.55), anosmia (0.58, 0.47-0.71), facial paralysis (0.35, 0.29-0.41), dysgeusia (0.68, 0.62-0.73), presyncope (0.48, 0.42-0.55), syncope (0.63, 0.58-0.67), and anxiety (0.75 (0.67-0.85).

CONCLUSION

Neurological and psychiatric AEFIs were relatively infrequent, but each vaccine was associated with a distinctive toxic profile.

Effectiveness and Cost-Effectiveness of Inactivated Vaccine to Address COVID-19 Pandemic in China: Evidence From Randomized Control Trials and Real-World Studies

Objective

This study aimed to determine the efficacy, effectiveness, and cost-effectiveness of inactivated COVID-19 vaccines (CoronaVac and BBIBP-CorV) in China using existing international clinical trials and real-world evidence.

Methods

Through a search of PubMed, Embase, Web of Science, and CNKI, studies investigating the effectiveness of inactivated COVID-19 vaccines were identified, and a meta-analysis was undertaken to synthesize the vaccine efficacy and effectiveness data. Moreover, a decision-analytic model was developed to estimate the cost-effectiveness of inactivated vaccines for combating the COVID-19 pandemic in the Chinese context from a societal perspective. Results of the meta-analysis, along with cost data from official websites and works of literature were used to populate the model. Sensitivity analysis was performed to test the robustness of the model results.

Results

A total of 24 studies were included in the meta-analysis. In comparison to no immunization, the effectiveness of inactivated vaccine against COVID-19 infection, hospitalization, ICU admission and death were 65.18% (95% CI 62.62, 67.75), 79.10% (95% CI 71.69, 86.51), 90.46% (95% CI 89.42, 91.50), and 86.69% (95% CI 85.68, 87.70); and the efficacy against COVID-19 infection and hospitalization were 70.56% (95% CI 57.87, 83.24) and 100% (95% CI 61.72, 100). Inactivated vaccine vaccination prevented more infections, hospitalizations, ICU admissions, and deaths with lower total costs, thus was cost-saving from a societal perspective in China. Base-case analysis results were robust in the one-way sensitivity analysis, and the percentage of ICU admission or death and direct medical cost ranked the top influential factors in our models. In the probabilistic sensitivity analysis, vaccination had a 100% probability of being cost-effective.

Conclusion

Inactivated vaccine is effective in preventing COVID-19 infection, hospitalization, ICU admission and avoiding COVID-19 related death, and COVID-19 vaccination program is cost-saving from societal perspective in China.

The Vaccine Efficacy Against the SARS-CoV-2 Omicron: A Systemic Review and Meta-Analysis

Background

COVID-19 is a respiratory illness caused by SARS-CoV-2. The most recent variant is Omicron (line B.1.1.529), which was first identified in South Africa in November 2021. The concern with this variant is the ineffectiveness of vaccines currently available. We aim to systematically evaluate the effectiveness of the currently available COVID-19 vaccines and boosters for the Omicron variant.

Methods

We searched the PubMed, Embase, the Cochrane Library and Web of Science databases from inception to June 5th, 2022. Studies that examined the effectiveness of SARS-CoV-2 vaccines against the Omicron variant infection were included. Random-effects model was used to estimate the pooled vaccine effectiveness against the Omicron variant.

Results

A total of 13 studies were included to evaluate the effectiveness of the vaccine against the Omicron variant, and 11 studies were included to compare the effectiveness between the two-dose and three-dose (booster) vaccinations. Full vaccination (two-dose with or without booster) showed a protective effect against the Omicron variant compared to no vaccination (OR = 0.62, 95% CI: 0.56–0.69), while the effectiveness decreased significantly over 6 months after the last dose. The two-dose vaccination plus booster provided better protection against the Omicron variant compared to the two-dose vaccination without booster (OR = 0.60, 95% CI: 0.52–0.68). Additional analysis was performed for the most commonly used vaccines in the United Staes: BNT162b2(Pfizer) (OR = 0.65, 95% CI: 0.52–0.82) and mRNA-1273(Moderna) (OR = 0.67, 95% CI: 0.58–0.88) vaccines in the US, which showed similar effectiveness compared to no vaccination.

Conclusions

The full dose of SARS-CoV-2 vaccination effectively reduces infection from the SARS-CoV-2 Omicron variant; however, the effectiveness wanes over time. The booster vaccine provides additional protection against the Omicron variant.

Comparing Reactogenicity of COVID-19 vaccines: a systematic review and meta-analysis

OBJECTIVES

A number of vaccines have now been developed against COVID-19. Differences in reactogenicity and safety profiles according to the vaccine technologies employed are becoming apparent from clinical trials.

METHODS

Five databases (Medline, EMBASE, Science Citation Index, Cochrane Central Register of Controlled Trials, London School of Hygiene and Tropical Medicine COVID-19 vaccine tracker) were searched for relevant randomised controlled trials between 1 January 2020 and 12 January 2022 according to predetermined criteria with no language limitations.

RESULTS

Forty-two datasets were identified, with 20 vaccines using four different technologies (viral vector, inactivated, mRNA and protein sub-unit). Adults and adolescents over 12 years were included. Control groups used saline placebos, adjuvants, and comparator vaccines. The most consistently reported solicited adverse events were fever, fatigue, headache, pain at injection site, redness, and swelling. Both doses of mRNA vaccines, the second dose of protein subunit and the first dose of adenovirus vectored vaccines were the most reactogenic, while the inactivated vaccines were the least reactogenic.

CONCLUSIONS

The different COVID-19 vaccines currently available appear to have distinct reactogenicity profiles, dependent on the vaccine technology employed. Awareness of these differences may allow targeted recommendations for specific populations. Greater standardization of methods for adverse event reporting will aid future research in this field.

Clinical characteristics, radiological features and prognostic factors of transverse myelitis following COVID-19 vaccination: A systematic review

Background

Since introducing COVID-19 vaccines, many neurological complications such as acute transverse myelitis have been reported in the literature. This study aims to identify the clinical characteristics, radiological findings, and prognostic factors in patients with COVID-19 vaccine-associated transverse myelitis (TM).

Methods

We systematically reviewed Scopus, Pubmed, Cochrane library, Google Scholar, and preprint databases using appropriate keywords from inception till 8th April 2022. Besides, we manually searched the reference lists of the included studies and relevant previous reviews.

Results

We included 28 studies identifying 31 post-COVID-19 vaccination myelitis patients (17 female and 14 male). The mean age of the included patients was 52±19 years. ChAdOx1 nCoV-19 vaccine (Oxford-AstraZeneca) was the most common type of vaccine in association with myelitis (12 out of 31), followed by Pfizer (8 out of 31), Moderna (7 out of 31), Sinopharm (3 out of 31), and Janssen vaccine (1 out of 31). The myelitis occurred in 24 and 7 patients after administering the first and second dose of the vaccine, respectively. 21 and 10 patients had good recovery (Modified Rankin Score (MRS) <3 at the follow-up) and poor recovery (MRS≥3 at the follow-up) from myelitis, respectively. Age (OR 1.09, 95%CI 1.01–1.18, p_value 0.02), and MRS at admission (OR 17.67, 95%CI 1.46–213.76, p_value 0.024) were two independent risk factors for poor recovery from myelitis.

Conclusion

The patients with higher age and MRS at admission had a worse prognosis and needed timely and more aggressive therapeutic strategies.

Safety and efficacy of COVID-19 vaccines in children and adolescents: A systematic review of randomized controlled trials

To systematically review and synthesize the safety and efficacy of coronavirus disease‐2019 (COVID‐19) vaccines in children and adolescents. PubMed, EMBASE, Web of Science, Cochrane Library databases, the International Clinical Trials Registry Platform (ICTRP), the Chinese Clinical Trials Registry (ChiCTR), and ClinicalTrials.gov website were searched to collect accessible randomized controlled trials (RCTs) about the safety and efficacy of human COVID‐19 vaccines in children and adolescents until May 1, 2022. Three steps, including duplicate removal, title and abstract screening, and full‐text review, were used to screen the studies. The Cochrane risk‐of‐bias tool for RCTs was used to assess the bias risk of the included studies. Microsoft Excel 16.57 (2021) software was used for data extraction and analysis. (PROSPERO Code No: CRD42021295422). COVID‐19 vaccines were evaluated in a total of 10 950 children and adolescents in seven published studies and over 49 530 participants in 26 ongoing randomized controlled trials. Descriptive findings of the included published studies were reported stratified by vaccine type. The overall, local, and systemic adverse events following immunization (AEFIs) reported in most trials were similar between the vaccine and placebo groups. Most of the reactions reported were mild to moderate, whereas a few were severe. The common adverse events were injection‐site pain, fever, headache, cough, fatigue, and muscle pain. Few clinical trials reported serious adverse events, but most of them were unrelated to vaccination. In terms of efficacy, the investigated messenger RNA (mRNA) vaccine was found to be 90.7%–100% efficacious in preventing COVID‐19 among children and adolescents, revealing good efficacy profiles in this age group. Among children and adolescents, the safety of current COVID‐19 vaccines is acceptable, and studies have suggested that mRNA vaccines can provide high protection against COVID‐19 infection in pediatric age groups.

Detection of Platelet-Activating Antibodies Associated with Vaccine-Induced Thrombotic Thrombocytopenia by Flow Cytometry: An Italian Experience

Rare cases of thrombocytopenia and thrombosis after anti-COVID-19 adenovirus-associated mRNA vaccines (VITT) due to platelet-activating anti-platelet-factor 4 (PF4)/polyanion antibodies have been reported. VITT laboratory diagnosis, similarly to heparin-induced thrombocytopenia (HIT) diagnosis, requires immunoassays for anti-PF4/polyanion antibodies identification, such as ELISA assays and platelet-activating functional tests, such as heparin-induced platelet activation test (HIPA), to confirm their pathogenicity. We compared the flow cytometry (FC) measurement of platelet p-selectin exposure to the gold standard functional test HIPA for diagnosis confirmation in 13 patients with a clinical VITT syndrome (6M/7F; median age 56 (33–78)) who resulted positive to anti-PF4/polyanion antibodies ELISA assays (12/13). FC and HIPA similarly identified three different patterns: (1) a typical non-heparin-dependent VITT pattern (seven and six patients by FC and HIPA, respectively); (2) low/no platelet activation in patients under IvIg therapy (five out of five and two out of four patients by FC and HIPA, respectively); (3) a HIT pattern. Antibodies investigated by FC became negative after 7, 17, and 24 days of therapy in three patients. FC measurement of P-selectin exposure was as sensitive as HIPA but simpler to detect anti-PF4/polyanion antibodies in VITT patients. FC could reliably discriminate VITT from HIT, thus helping for the choice of the anticoagulant.

Investigation of factors affecting COVID-19 vaccine acceptance among communities of universities in the United Arab Emirates

The COVID-19 pandemic affected the lives of people living across the world and the development of vaccines against SARS-CoV-2 is considered to be one of the most promising solutions to contain the COVID-19 pandemic. In several countries, we are witnessing hesitancy toward COVID-19 vaccines, which is a complex phenomenon influenced by a variety of factors. A cross-sectional study was performed to comprehensively investigate the impact of factors like demography, COVID-19 pandemic-induced behavior, and vaccine attitude on COVID-19 vaccine acceptance (VA) among communities of five different universities in the United Arab Emirates (UAE). To investigate the effect of demography and COVID-19 pandemic-induced behavioral factors, Analysis of Variance was perfomed. The effect of COVID-19 vaccine attitudes on COVID-19 VA was examined through partial least squares-structural equations modeling. The results of the study showed no difference among the population in accepting COVID-19 vaccines due to their demographic factors. The effect of pandemic-induced behavioral factors on COVID-19 VA suggested that the people of UAE accepted COVID-19 vaccines irrespective of the movement and travel restrictions imposed due to the pandemic. The results on the effect of vaccine attitudes on COVID-19 VA showed that vaccine benefit attitudes, safety concerns, and trust in health-care professionals (TrHP) were found to be significant factors in VA. Furthermore, TrHP was found to reduce the negative effect of safety concerns related to COVID-19 VA. The findings broadly highlight that COVID-19 VA in the UAE was not hampered by demographic factors and the pandemic-induced behavioral constraints. The study also showed that people with co-morbidities had lower level of COVID-19 VA than people with no co-morbidities. To improve COVID-19 VA, the perceived benefits with COVID-19 vaccine and TrHP must be enhanced and simultaneously safety concerns of the vaccines need to be addressed.

SARS-CoV-2 and Emerging Variants: Unmasking Structure, Function, Infection, and Immune Escape Mechanisms

As of April 1, 2022, over 468 million COVID-19 cases and over 6 million deaths have been confirmed globally. Unlike the common coronavirus, SARS-CoV-2 has highly contagious and attracted a high level of concern worldwide. Through the analysis of SARS-CoV-2 structural, non-structural, and accessory proteins, we can gain a deeper understanding of structure-function relationships, viral infection mechanisms, and viable strategies for antiviral therapy. Angiotensin-converting enzyme 2 (ACE2) is the first widely acknowledged SARS-CoV-2 receptor, but researches have shown that there are additional co-receptors that can facilitate the entry of SARS-CoV-2 to infect humans. We have performed an in-depth review of published papers, searching for co-receptors or other auxiliary membrane proteins that enhance viral infection, and analyzing pertinent pathogenic mechanisms. The genome, and especially the spike gene, undergoes mutations at an abnormally high frequency during virus replication and/or when it is transmitted from one individual to another. We summarized the main mutant strains currently circulating global, and elaborated the structural feature for increased infectivity and immune evasion of variants. Meanwhile, the principal purpose of the review is to update information on the COVID-19 outbreak. Many countries have novel findings on the early stage of the epidemic, and accruing evidence has rewritten the timeline of the outbreak, triggering new thinking about the origin and spread of COVID-19. It is anticipated that this can provide further insights for future research and global epidemic prevention and control.

Persistence of Naturally Acquired and Functional SARS-CoV-2 Antibodies in Blood Donors One Year after Infection

The developmental course of antibodies produced after a SARS-CoV-2 infection has been insufficiently investigated so far. Therefore, the aim of this study was to investigate the dynamics of SARS-CoV-2 antibody levels against the viral nucleocapsid- and spike-protein among Austrian blood donors as a representative group of a supposedly healthy population within the first year after a SARS-CoV-2 infection. The impact of age, sex, vaccination status, AB0-blood group and awareness about the infection was evaluated. Our study shows that the level of anti-N antibodies is declining, while anti-S antibody levels remain stable. Antibodies detected were functional in vitro. Age, sex and blood group do not influence antibody dynamics. However, blood group AB shows significantly lower antibody levels and in vitro functionality compared to other blood groups. Our data reveal that one out of five individuals was not aware of a previous SARS-CoV-2 infection and that the disease course neither affects the level of antibody production nor the in vitro functionality. We also found that 14% of participants show persisting COVID-19-related symptoms for up to nine months. Our results provide valuable insights into the dynamics of the immune response after a SARS-CoV-2 infection in a representative cohort of adult blood donors in Central Europe.

Association of COVID-19 vaccination with herpes zoster: a systematic review and meta-analysis

BACKGROUND

Following COVID-19 vaccination, several herpes zoster cases have been reported, making it critical to explore the association between herpes zoster and COVID-19 vaccination. This is especially true in the context of increasing the number of participants enrolled to receive COVID-19 vaccination.

RESEARCH DESIGN AND METHODS

Three databases, including the Cochrane Library, PubMed, and EMBASE, were searched for relevant studies before December 25, 2021, according to preliminarily determined inclusion and exclusion criteria without any language limitations. Four cohort studies were included in this systematic review and meta-analysis.

RESULTS

Compared with the placebo group, there was no evidence that the COVID-19 vaccination group was associated with increased incidence of herpes zoster (Risk ratio [RR]: 1.06; 95% confidence interval [CI]: 0.91 to 1.24). There is no evidence that the COVID-19 vaccination from Moderna is associated with the incidence of herpes zoster compared with vaccination from Pfizer (RR: 0.20; 95% CI: 0.01 to 2.99).

CONCLUSIONS

To date, there is no evidence of an association between covid-19 vaccination and herpes zoster.

A systematic review of cases of CNS demyelination following COVID-19 vaccination

BACKGROUND

Since the emergency use approval of different types of COVID-19 vaccines, several safety concerns have been raised regarding its early and delayed impact on the nervous system.

OBJECTIVE

This study aims to systematically review the reported cases of CNS demyelination in association with COVID-19 vaccination, which has not been performed, to our knowledge.

METHODS

A systematic review was performed by screening published articles and preprints of cases of CNS demyelination in association with COVID-19 vaccines in PubMed, SCOPUS, EMBASE, Google Scholar, Ovid and medRxiv databases, until September 30, 2021. This study followed PRISMA guidelines. Descriptive findings of reported cases were reviewed and stratified by demographic and clinical findings, diagnostic work-up, management, and overall outcome.

RESULTS

A total of 32 cases were identified, with female predominance (68.8%) and median age of 44 years. Eleven cases were reported after Pfizer vaccine, 8 following AstraZeneca vaccine, 6 following Moderna, 5 following Sinovac/ Sinopharm vaccines, and one following each of Sputnik and Johnson&Johnson vaccines. The majority of cases (71.8%) occurred after the first dose of the vaccine, with neurological symptoms manifesting after a median of 9 days. The most common reported presentations were transverse myelitis (12/32) and MS-like pictures (first diagnosis or a relapse) in another 12/32 cases, followed by ADEM- like (5/32), and NMOSD- like (3/32) presentations. History of a previous immune-mediated disease was reported in 17/32 (53.1%) cases. The mRNA-based vaccines resulted in the greatest number of demyelinating syndromes (17/32), followed by viral vector vaccines (10/32), and inactivated vaccines (5/32). Most MS-like episodes (9/12) were triggered by mRNA-based vaccines, while TM occurred following both viral vector and mRNA-based vaccines. Management included high dose methylprednisolone, PLEX, IVIg, or a combination of those, with a favorable outcome in the majority of case; marked/complete improvement (25/32) or stabilized/ partial recovery in the remaining cases.

CONCLUSION

This systematic review identified few cases of CNS demyelination following all types of approved COVID-19 vaccines so far. Clinical presentation was heterogenous, mainly following the first dose, however, half of the reported cases had a history of immune-mediated disease. Favorable outcome was observed in most cases. We suggest long-term post-marketing surveillance for these cases, to assess for causality, and ensure the safety of COVID-19 vaccines.

Criteria for judging the immune markers of COVID-19 disease vaccines

As severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) sweeping the world, effective and affordable vaccines are in urgent need. A reliable system for the assessment of SARS‐CoV‐2 vaccines would boost the development of vaccines and reduce the research cost. We constructed a logistic regression model and analyzed the relationship between antibody (Ab) level and efficacy of different vaccine types. The relationship between assessment dates and Ab levels was depicted by plotting the mean of Ab levels evolved over time and a fitted cubic polynomial model. Anti‐spike immunoglobulin G (IgG) could best estimate the vaccine efficacy (VE) (adjusted R² = 0.731) and neutralizing Ab to live SARS‐CoV‐2 also explained a fine relationship (adjusted R² = 0.577). Neutralizing Abs to live SARS‐CoV‐2 in inactivated virus vaccines reached a peak during days 40–60, and their receptor‐binding domain (RBD)‐IgG peaked during days 40–50. For messenger RNA (mRNA) and viral vector vaccines, their neutralizing Ab to live SARS‐CoV‐2 peaked later than day 40, and for RBD‐IgG during days 30–50. For mRNA and viral vector vaccines, their peak time of Abs was later than that in inactivated virus vaccines. RBD‐IgG peaked earlier than Ab to live SARS‐CoV‐2. Anti‐spike IgG and Ab to live SARS‐CoV‐2 may be good immune markers for VE assessment.

Adenovirus Biology, Recombinant Adenovirus, and Adenovirus Usage in Gene Therapy

Gene therapy is currently in the public spotlight. Several gene therapy products, including oncolytic virus (OV), which predominantly replicates in and kills cancer cells, and COVID-19 vaccines have recently been commercialized. Recombinant adenoviruses, including replication-defective adenoviral vector and conditionally replicating adenovirus (CRA; oncolytic adenovirus), have been extensively studied and used in clinical trials for cancer and vaccines. Here, we review the biology of wild-type adenoviruses, the methodological principle for constructing recombinant adenoviruses, therapeutic applications of recombinant adenoviruses, and new technologies in pluripotent stem cell (PSC)-based regenerative medicine. Moreover, this article describes the technology platform for efficient construction of diverse "CRAs that can specifically target tumors with multiple factors" (m-CRAs). This technology allows for modification of four parts in the adenoviral E1 region and the subsequent insertion of a therapeutic gene and promoter to enhance cancer-specific viral replication (i.e., safety) as well as therapeutic effects. The screening study using the m-CRA technology successfully identified survivin-responsive m-CRA (Surv.m-CRA) as among the best m-CRAs, and clinical trials of Surv.m-CRA are underway for patients with cancer. This article also describes new recombinant adenovirus-based technologies for solving issues in PSC-based regenerative medicine.

Safety and effectiveness of SARS-CoV-2 vaccines: A systematic review and meta-analysis

OBJECTIVE

To systematically evaluate the effectiveness and safety of the SARS-CoV-2 vaccines currently undergoing clinical trials.

METHODS

PubMed, EMBASE, and Cochrane Library databases were searched to collect open human COVID-19 vaccines randomized controlled trials, without limiting the search time and language. The research papers collected in the above-mentioned databases were initially screened according to the title and abstract content and merged, and the repeated ones were removed. After reading the full text of the remaining research, the studies that did not meet the inclusion criteria were excluded, and finally, nine studies were obtained. After extracting the statistical data of adverse events in the study, load them into Review Manager for heterogeneity analysis.

RESULTS

The incidence of adverse reactions of inactivated virus vaccines, RNA vaccines, and adenovirus vector vaccines was higher than that of placebo. Common adverse reactions included pain, swelling, and fever at the injection site.

CONCLUSION

From the perspective of effectiveness, RNA vaccine > adenovirus vector vaccine > inactivated virus vaccine. From the perspective of safety, the incidence of adverse reactions of the three vaccines is higher than that of a placebo, and the incidence of adverse reactions of the adenovirus vector vaccine is higher.

A Local Survey of COVID-19: Vaccine Potential Acceptance Rate among Personnel in a Level 1 Trauma Center without Severe COVID-19 Cases

BACKGROUND

Healthcare workers (HCWs) in hospitals are at high risk during the COVID-19 pandemic. Healthcare workers' infection risk could be amplified during the ongoing pandemic due to various factors, including continuous exposure to patients and inadequate infection control training. Despite the risk healthcare workers face, vaccine hesitancy remains a global challenge. Differences in acceptance rates have ranged from less than 55% (in Russia) to nearly 90% (in China). In order to improve our knowledge of vaccine acceptance and its variation in rates, an evaluation is warranted. A survey was thus administered to healthcare workers.

METHODS

This survey aimed to address vaccination acceptance among employees in an urban level 1 trauma hospital. It was conducted through a developed and structured questionnaire that was randomly distributed online among the staff (age ≥18 years) to receive their feedback.

RESULTS

Among 285 participants (out of 995 employees), 69% were female, and 83.5% were overaged more than 30 years of age. The two largest groups were nurses (32%) and doctors (22%). The majority of respondents reported that they would "like to be vaccinated" (77.4%) and that they trusted the COVID-19 vaccine (62%). Moreover, 67.8% also reported that they felt the vaccination was effective. They reported that vaccination was a method to prevent the spread of COVID-19 (85.15%) and was a way to protect individuals with weak immune systems (78.2%). More importantly, the participants were concerned about other people (80.1%) and believed the vaccine would protect others. On the other hand, the result showed that the majority of participants (95.3%) chose to be vaccinated once everyone else was vaccinated, "I don't need to get vaccinated". Results showed that the majority of participants that chose "I don't need to get vaccinated" did so after everyone else was vaccinated. Our results show that COVID-19 vaccination intention in a level 1 trauma hospital was associated with older age males who are more confident, and also share a collective responsibility, are less complacent, and have fewer constraints.

CONCLUSION

Acceptance of the COVID-19 vaccine is relatively low among healthcare workers (HCWs). Differences in vaccine acceptance have been noted between different categories of HCWs and genders. Therefore, addressing barriers to vaccination acceptance among these HCWs is essential to avoid reluctance to receive the vaccination, but it will be challenging.

Effectiveness and safety of SARS-CoV-2 vaccine in real-world studies: a systematic review and meta-analysis

BACKGROUND

To date, coronavirus disease 2019 (COVID-19) becomes increasingly fierce due to the emergence of variants. Rapid herd immunity through vaccination is needed to block the mutation and prevent the emergence of variants that can completely escape the immune surveillance. We aimed to systematically evaluate the effectiveness and safety of COVID-19 vaccines in the real world and to establish a reliable evidence-based basis for the actual protective effect of the COVID-19 vaccines, especially in the ensuing waves of infections dominated by variants.

METHODS

We searched PubMed, Embase and Web of Science from inception to July 22, 2021. Observational studies that examined the effectiveness and safety of SARS-CoV-2 vaccines among people vaccinated were included. Random-effects or fixed-effects models were used to estimate the pooled vaccine effectiveness (VE) and incidence rate of adverse events after vaccination, and their 95% confidence intervals (CI).

RESULTS

A total of 58 studies (32 studies for vaccine effectiveness and 26 studies for vaccine safety) were included. A single dose of vaccines was 41% (95% CI: 28-54%) effective at preventing SARS-CoV-2 infections, 52% (31-73%) for symptomatic COVID-19, 66% (50-81%) for hospitalization, 45% (42-49%) for Intensive Care Unit (ICU) admissions, and 53% (15-91%) for COVID-19-related death; and two doses were 85% (81-89%) effective at preventing SARS-CoV-2 infections, 97% (97-98%) for symptomatic COVID-19, 93% (89-96%) for hospitalization, 96% (93-98%) for ICU admissions, and 95% (92-98%) effective for COVID-19-related death, respectively. The pooled VE was 85% (80-91%) for the prevention of Alpha variant of SARS-CoV-2 infections, 75% (71-79%) for the Beta variant, 54% (35-74%) for the Gamma variant, and 74% (62-85%) for the Delta variant. The overall pooled incidence rate was 1.5% (1.4-1.6%) for adverse events, 0.4 (0.2-0.5) per 10 000 for severe adverse events, and 0.1 (0.1-0.2) per 10 000 for death after vaccination.

CONCLUSIONS

SARS-CoV-2 vaccines have reassuring safety and could effectively reduce the death, severe cases, symptomatic cases, and infections resulting from SARS-CoV-2 across the world. In the context of global pandemic and the continuous emergence of SARS-CoV-2 variants, accelerating vaccination and improving vaccination coverage is still the most important and urgent matter, and it is also the final means to end the pandemic.

Safety and immunogenicity of inactivated SARS-CoV-2 vaccines in healthy individuals: protocol for a systematic review and meta-analysis

INTRODUCTION

COVID-19 has spread with high morbidity and mortality worldwide. Many inactivated SARS-CoV-2 vaccines are being tested at various clinical trial stages for the control and prevention of COVID-19. We aim to comprehensively and objectively evaluate the safety and immunogenicity of inactivated SARS-CoV-2 vaccines in healthy individuals through a systematic review and meta-analysis of randomised controlled trials (RCTs).

METHODS AND ANALYSIS

We will search electronic databases of PubMed, the Cochrane Library, Web of Science and EMBASE for RCTs from inception to 31 December 2021. We will also search conference abstracts, reference lists, and grey literature of all available records. Two reviewers will independently screen and extract information from the literature. Bias and the quality of included studies will be evaluated with the risk-bias assessment tool provided by the Cochrane Collaboration. Statistical analysis will be performed using Cochrane's Review Manager (RevMan), V.5.3.

ETHICS AND DISSEMINATION

Ethics approval and patient informed consent are not required because we will be including published literature only. The findings of this research will be disseminated in a peer-reviewed journal and likely through other scientific events such as conferences, seminars and symposia.

PROSPERO REGISTRATION NUMBER

CRD42021266285.