BNT162b2 mRNA COVID-19 Vaccine Effectiveness in the Prevention of SARS-CoV-2 Infection and Symptomatic Disease in Five-Month Follow-Up: A Retrospective Cohort Study

Consequences of COVID-19 Vaccine Hesitancy Among Healthcare Providers During the First 10 Months of Vaccine Availability: Scoping Review

BACKGROUND

Throughout the COVID-19 pandemic, healthcare providers (HCPs)-including nurses-have played important roles in the vaccination effort. It is expected that COVID-19 vaccine hesitancy among HCPs has numerous consequences; however, the scope of these consequences and their impacts on providers, patients, and the broader healthcare system remained unclear.

PURPOSE

To identify existing and emerging evidence to understand the state of knowledge of the consequences of COVID-19 vaccine hesitancy among HCPs.

METHODS

A scoping review was completed based upon the JBI scoping review methodology. The databases searched included OVID Medline, EBSCOhost CINAHL, ProQuest Nursing and Allied Health Source, ProQuest APA PsycInfo, and ProQuest Dissertations and Theses. The final literature search was completed on June 2, 2022. Studies were screened and retrieved based on predefined inclusion and exclusion criteria using Covidence reference management software. Data extraction followed criteria recommended in the JBI scoping review framework with additional relevant variables identified by the authors.

RESULTS

A total of 33 sources were included in the review. Consequences of HCP COVID-19 vaccine hesitancy were grouped under three themes and seven subthemes. Consequences affecting HCPs included health-related, psychosocial, and employment-related consequences. Consequences affecting patients pertained to COVID-19 vaccination communication and COVID-19 vaccination practices of HCPs. Consequences to the healthcare system involved consequences to coworkers and employment/attendance/staffing-related consequences.

CONCLUSIONS

Healthcare provider COVID-19 vaccine hesitancy was found to have numerous consequences. By understanding the scope and extent of these consequences, healthcare leaders, researchers, and HCPs can work together to protect providers, patients, and healthcare systems.

Immunogenicity after vaccination of COVID-19 vaccines in patients with cancer: a prospective, single center, observational study

BACKGROUND

Patients with cancer, particularly those undergoing chemotherapy, are at risk from the low immunogenicity of Coronavirus Disease 19 (COVID-19) vaccines.

METHODS

This prospective study assessed the seroconversion rate of COVID-19 vaccines among patients with cancer and hospital staff. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein-specific IgG (S-IgG) concentrations were evaluated before the first vaccination, and 1-3 and 4-6 months after the second vaccination. The primary endpoint was the seroconversion rate measured 1-3 months after the second vaccine.

RESULTS

In total, 590 patients and 183 healthy hospital staff were analyzed. At 1-3 months after the second vaccination, the S-IgG antibody concentration exceeded the cut-off value (20 BAU/mL) in 96.1% (567/590) of the patients with cancer and 100% (183/183) of the healthy controls (p = 0.0024). At 4-6 months after the second vaccination, the S-IgG antibody concentration exceeded the cut-off value (20 BAU/ml for S-IgG) in 93.1% (461/495) of the patients with cancer and 100% (170/170) of the healthy controls (p < 0.0001). Old age, being male, and low lymphocyte count were related to low SARS-CoV-2 S-IgG levels 1-3 months after the second vaccination among patients, while body mass index, smoking history, and serum albumin level were not. Patients undergoing platinum combination therapy and alkylating agent among cytotoxic drugs, and PARP inhibitor, mTOR inhibitor, and BCR-ABL inhibitor exhibited a low S-IgG antibody concentration compared to the no treatment group.

CONCLUSIONS

COVID-19 vaccine immunogenicity was reduced among patients with cancer, especially under several treatment regimens.

COVID-19 vaccination hesitancy among Italian parents: A systematic review and meta-analysis

In May 2021, the Italian government extended the COVID-19 vaccination campaign to 12- to 18-year-old subjects and, starting December 2021, vaccines were also offered to children between 5 and 11 years-old. Despite these efforts, suboptimal vaccination coverages are reported. The purpose of this review is to estimate the proportion of parents/caregivers of children and adolescents expressing COVID-19 vaccine hesitancy in Italy. The vaccine hesitation rate among parents of minors was 55.1% (95%CI: 43.8-66.1%). A higher value was evidenced in studies focusing on children (59.9%; 95%CI = 43.7-75.1%) compared to the ones focusing on adolescents (51.3%; 95%CI = 34.5-68.0%). The main reasons for unwillingness were the belief that the vaccine was unsafe or ineffective, fear of adverse events, and considering COVID-19 a non-threatening disease. The implementation of effective communication campaigns and health educational programs on safe pediatric vaccinations is essential to support strategies to bolster vaccination confidence.

Determinants of compliance to influenza and COVID-19 vaccination in a cohort of solid organ transplant patients in Puglia, Southern Italy (2017-2022)

Influenza and Coronavirus Disease 2019 (COVID-19) vaccination are recommended in both solid organ transplant (SOT) candidates and recipients. In Puglia, Southern Italy, an active vaccination offer program has been activated targeting these patients. This study aims at investigating vaccination coverage (VC) for both vaccines in a SOT patients' cohort, as well as at identifying the vaccination compliance determinant. This is a retrospective, population-based study. The study population consists of the SOT patients who accessed Bari's "Policlinico" General Hospital during 2017-2022. Patients were contacted and, after providing their consent, asked their immunization status regarding influenza and COVID-19 and whether they had already undergone transplant or were waiting to do so. Regression models were fitted to investigate the determinants of VCs for influenza vaccination (2021/22 and 2022/23 seasons) and for COVID-19 vaccination (three-dose base cycle, first and second booster doses). Three-hundred and ten SOT patients were identified; 85.2% (264/310) had already undergone SOT. VCs were suboptimal, especially for constant yearly influenza vaccination (17.7%) and COVID-19 vaccination's second booster (1.94%). Logistic regression highlighted that influenza VCs are higher for SOT recipients than SOT candidates, as well as for older patients, although when considering both vaccination seasons only age significantly impact the vaccination uptake. Older age was the only influential variable for COVID-19 VC. VCs for SOT patients seem to be unsatisfying. Stronger interventions are required.

A panoramic view of hospitalized young children in the metropolitan area of the valley of Mexico during COVID-19

Objectives

This work provides an overview of young children's (aged 0-9) infectious diseases epidemiology, by exploring the link between various comorbid conditions, COVID-19, and death rate.

Methods

Public data on hospitalized young children was obtained from national databases of the Mexican health care system from 2020-2022. Data included age, year of entry, gender, the time between admission to death (hospitalization time), date of death, comorbidities, and admissions to the intensive care unit. Children were separated into age groups and frequencies were calculated. Binary regression models were developed to determine the correlation of comorbidities and COVID-19 to death as calculated by odds ratios (OR).

Results

From 2020-2022, there were 11,815 hospitalizations among young children, of which 15.98% were due to COVID-19, 2.55% of hospitalizations resulted in fatalities from which 32.45% of deaths were COVID-19 related. The highest case-calculated fatality ratio of COVID-19 infected young children was estimated at 7.04% by early 2020, but dropped to 2.11% by the end of the second semester of 2022. The most frequent comorbidities associated with their hospitalization and death for the general population were intubation (OR: 17.967), pneumonia (OR: 2.263), diabetes (OR: 7.301), cardiovascular diseases (OR: 1.528) and COVID-19 (OR: 261). For the COVID-19-positive group, the most impactful comorbidities were intubation (OR: 20.232), pneumonia (OR: 3.057), and diabetes (OR: 12.824).

Conclusion

Children's hospitalizations and deaths were common during the pandemic; wherein major comorbidities played an important role. Therefore, effective comorbidity management and vaccination programs are essential to reduce hospitalizations and deaths among young children.

Vaccine efficacy against SARS-CoV-2 for Pfizer BioNTech, Moderna, and AstraZeneca vaccines: a systematic review

The purpose of this systematic review was to report on the vaccine efficacy (VE) of three SARS-CoV-2 vaccines approved by Health Canada: Pfizer BioNTech, Moderna, and AstraZeneca. Four databases were searched for primary publications on population-level VE. Ninety-two publications matched the inclusion criteria, and the extracted data were separated by vaccine type: mRNA vaccines (Pfizer and Moderna) and the AstraZeneca vaccine. The median VE for PCR-positive patients and various levels of clinical disease was determined for the first and second doses of both vaccine types against multiple SARS-CoV-2 variants. The median VE for PCR-positive infections against unidentified variants from an mRNA vaccine was 64.5 and 89%, respectively, after one or two doses. The median VE for PCR-positive infections against unidentified variants from the AstraZeneca vaccine was 53.4 and 69.6%, respectively, after one or two doses. The median VE for two doses of mRNA for asymptomatic, symptomatic, and severe infection against unidentified variants was 85.5, 93.2, and 92.2%, respectively. The median VE for two doses of AstraZeneca for asymptomatic, symptomatic, and severe infection against unidentified variants was 69.7, 71, and 90.2%, respectively. Vaccine efficacy numerically increased from the first to the second dose, increased from the first 2 weeks to the second 2 weeks post-vaccination for both doses, but decreased after 4 months from the second dose. Vaccine efficacy did not differ by person's age.

Safety profile and SARS-CoV-2 breakthrough infections among HCWs receiving anti-SARS-CoV-2 and influenza vaccines simultaneously: an Italian observational study

In October/December 2021, World Health Organization and other international agencies recommended the offer of the third dose of anti-SARS-CoV-2 vaccine. In this period, the routine offer of seasonal influenza vaccination was also guaranteed and simultaneous administration of the two vaccines was encouraged. This study aims to evaluate the safety profile and to estimate the incidence of SARS-CoV-2 breakthrough infections in subjects receiving the anti-SARS-CoV-2 and influenza vaccines simultaneously. The study population was represented by healthcare workers (HCWs) of Bari Policlinico General Hospital who received the influenza (Flucelvax Tetra®) and/or anti-SARS-CoV-2 vaccination (BNT162b2 mRNA COVID-19 vaccine, Comirnaty®) either in coadministration or separately in October 2021. Reports of adverse events following immunization (AEFIs) were investigated to study the safety of both vaccines in coadministration and in separate-instance administration. Post-vaccination SARS-CoV-2 breakthrough infection was also studied. 942 HCWs accepted to join our study. 610/942 received both vaccines simultaneously. 25.26 % subjects (238/942) were only vaccinated against SARS-CoV-2, while the remaining 94 HCWs received the influenza vaccination first and subsequently received the anti-SARS-CoV2 booster dose. 717 HCWs reported AEFIs (Reporting Rate 76.1 per 100 subjects). Simultaneous administration of the two vaccines was not related with an increase of the rate of AEFIs compared to the single administration of SARS-CoV-2 vaccine, but the AEFIs' rate was lower among subjects who received only influenza vaccine. Post-vaccination SARS-CoV-2 infections were notified for 41.5 % of enrolled subjects (391/942). Incidence of breakthrough infection and symptomatic disease was not significantly different between the simultaneous administration group and other subjects. Our data suggests that simultaneous administration of a quadrivalent influenza vaccine and an mRNA anti-SARS-CoV-2 vaccine neither affected the safety of said products nor was associated with a higher risk of SARS-CoV-2 breakthrough infection.

COVID-19 vaccine acceptance and its determinants among residents of Ambo Town, West Shewa, Oromia Region, Ethiopia: cross-sectional survey

Background

Vaccines against COVID-19 are critical for preventing and managing COVID-19 because immunization is one of the most active and cost-effective health strategies for infectious disease prevention. Knowing the community's willingness and factors affecting COVID-19 vaccine acceptance will support the design of effective promotion strategies. Therefore, this study was aimed at assessing COVID-19 vaccine acceptance and its determinants among the Ambo Town community.

Method

A community-based, cross-sectional study was conducted using structured questionnaires from 1 to 28 February 2022. Four kebeles were selected randomly, and the systematic random sampling procedure was used to select the households. SPSS-25 software was used for data analysis. Ethical approval was received from the Institutional Review Committee of the College of Medicine and Health Sciences of Ambo University, and data were kept confidential.

Result

Of the 391 participants, 385 (98.5%) of the respondents were not vaccinated for COVID-19, and around 126 (32.2%) of the respondents said that they would receive the vaccine if the government provided it. The multivariate logistic regression analysis revealed that males were 1.8 times more likely to accept the COVID-19 vaccine (adjusted odds ratio (AOR) = 1.8, 95% CI: 1.074-3.156) as compared to females. The acceptance of the COVID-19 vaccine was lower by 60% in those who tested for COVID-19 as compared to those who were not tested (AOR = 0.4, 95% CI: 0.27-0.69). Moreover, the participants who had chronic diseases were two times more likely to accept the vaccine. Acceptance of the vaccine was reduced by half among those who believed that there was a scarcity of data on its safety (AOR = 0.5, 95% CI: 0.26-0.80).

Conclusion

The prevalence of COVID-19 vaccination acceptance was low. To enhance the acceptance of the COVID-19 vaccine, the government and different stakeholders should strengthen public education using mass media about the advantages of getting the COVID-19 vaccination.

Prevalence of poliovirus neutralizing antibodies in Italian population: A systematic review and meta-analysis

INTRODUCTION

The introduction of anti-poliomyelitis vaccines has driven progress toward the global eradication of wild polioviruses, a millennium goal of the World Health Organization. With the vaccination campaigns carried out since 1964, in 2002 Italy was certified polio-free, considering that no cases had been recorded since 1983. Nevertheless, it is crucial to guarantee high level of immunization coverage also in low-endemicity countries, considering that sporadic polio cases can be recorded. To evaluate the presence of susceptible subjects in the population, seroepidemiological studies are key actions.

METHODS

We conducted a systematic review of the relevant literature to evaluate the prevalence of anti-PV neutralizing antibodies in Italian population. Seven studies, selected among scientific articles available in MEDLINE/PubMed, ISI Web of Knowledge and Scopus and published from January 1, 2012, to November 15, 2022, were included.

RESULTS

The pooled prevalence of subjects without PV1 neutralizing antibodies was 6.4% (95%CI = 0.5-16.9), for PV2 it was 5.3% (95%CI = 0.4-14.2), and for PV3 it was 13.0% (95%CI = 4.0-25.7; I2 = 98.5%). Levels of neutralizing antibodies appears to decrease with increasing age; this decline is a proxy for the real risk factor, which is the time since the last vaccine dose.

CONCLUSIONS

Public health institutions must be aware of the risk of reintroduction of wild PV in polio-free countries and therefore they must keep high level of immunization in population and reinforce the active surveillance systems.

Predicting vaccine effectiveness against severe COVID-19 over time and against variants: a meta-analysis

Vaccine protection from symptomatic SARS-CoV-2 infection has been shown to be strongly correlated with neutralising antibody titres; however, this has not yet been demonstrated for severe COVID-19. To explore whether this relationship also holds for severe COVID-19, we performed a systematic search for studies reporting on protection against different SARS-CoV-2 clinical endpoints and extracted data from 15 studies. Since matched neutralising antibody titres were not available, we used the vaccine regimen, time since vaccination and variant of concern to predict corresponding neutralising antibody titres. We then compared the observed vaccine effectiveness reported in these studies to the protection predicted by a previously published model of the relationship between neutralising antibody titre and vaccine effectiveness against severe COVID-19. We find that predicted neutralising antibody titres are strongly correlated with observed vaccine effectiveness against symptomatic (Spearman [Formula: see text] = 0.95, p < 0.001) and severe (Spearman [Formula: see text] = 0.72, p < 0.001 for both) COVID-19 and that the loss of neutralising antibodies over time and to new variants are strongly predictive of observed vaccine protection against severe COVID-19.

Ultra-rapid rollout vaccination with BNT162b2 to reduce SARS-CoV-2 infections in the general population

This study aimed to determine the impact of ultra-rapid rollout vaccination on incidence of SARS-CoV-2 infection. Vaccination with BNT162b2 was provided to 66.9% of eligible residents of the Schwaz district in Tyrol, Austria, within six days per dose (first dose: 11–16 March 2021, second dose: 8–13 April 2021). Of 11,955 individuals enrolled at nine vaccination centers (median age 44.6 years; 51.3% female), 71 had incident SARS-CoV-2 over a six-month follow-up. Incidence rates per 100,000 person-weeks were 92.3 (95% confidence interval [CI]: 70.8–120.2) at weeks 1–5 and 6.4 (3.9–10.4) at ≥6 weeks after dose 1. In these two periods, effectiveness of the vaccination campaign to reduce incident SARS-CoV-2 was 58.6% (50.8%–65.2%) and 91.1% (89.6%–92.3%) in study participants and 28.3% (23.1%–33.0%) and 64.0% (61.7%–66.1%) in the Schwaz district, compared with districts with slower vaccination rollout. Therefore, the vaccination campaign in the Schwaz district illustrates the impact of accelerated vaccination rollout in controlling the pandemic.

•

This study accompanied an ultra-rapid rollout vaccination campaign in Austria

•

66.9% of eligible residents of the Schwaz district received BNT162b2 within 6 days

•

Over six months, SARS-CoV-2 incidence rate was 22.8 per 100.000 person-weeks

•

Effectiveness of the vaccination campaign was 91.1% at ≥6 weeks after the 1^st dose

The effectiveness of mRNA vaccines to prevent SARS-CoV-2 infection and hospitalisation for COVID-19 according to the time elapsed since their administration in health professionals in the Valencian Autonomous Community (Spain)

The objective was to understand the effectiveness of the BNT162b2 and mRNA-1273 vaccines against SARS-CoV-2 in health professionals(HPs) in the Valencian Autonomous Community(Spain) who had completed a full vaccination regimen, both in terms of preventing infections and avoiding hospitalisations, according to the time elapsed since the vaccine administration. Case-controlled study with negative test results. HPs who had undergone at least one PCR or antigen(Ag) active infection diagnostic test(AIDT) to rule out SARS-CoV-2 infection between 25 January and 18 July 2021 were included. HPs with positive AIDT result were considered as cases and those with a negative result controls. Adjusted vaccine effectiveness(VEa) to prevent SARS-CoV-2 infection and its 95% confidence interval(95% CI) were calculated using the formula VEa = (1 - OR) × 100. The VEa for the prevention of SARS-CoV-2 infection 12 to 120 days after completing the full two-dose vaccine regimen was 91.6%(95%CI[89.6%,93.2%]) for the BNT162b2 vaccine and 95.2%(95%CI[88.3%,98.1%]) for the mRNA-1273 vaccine. After 120 days the VEa was 71.5%(95%CI[67.0%,75.5%]) for the BNT162b2 vaccine and 88.3%(95%CI[75.7,94.4%]) for the mRNA-1273 vaccine. The VEa for prevention of hospitalisation for COVID-19 for the complete two-dose regimen of mRNA vaccines (BNT162b2 and mRNA-1273) was 96.8%(95%CI[76.1%,99.6%]). The administration of the complete regimen of the BNT162b2 and mRNA-1273 vaccine against SARS-CoV-2 was highly effective for the prevention of COVID-19 cases in HPs when 12 to 120 days had elapsed since the second dose. However, said effectiveness decreased as time from the vaccine administration elapsed, although it was maintained for the prevention of hospitalisation of HPs.

COVID-19 Severity and Mortality after Vaccination against SARS-CoV-2 in Central Greece

Background: Vaccination against SARS-CoV-2 (COVID-19) has become crucial for limiting disease transmission and reducing its severity, hospitalizations and mortality; however, despite universal acceptance, vaccine hesitancy is still significant. In the present manuscript, we aim to assess COVID-19-attributed mortality after the prevalence of new variants of the virus (Delta and Omicron viral strains) and to evaluate the vaccination effect. Methods: All patients that were hospitalized due to COVID-19 infection in the Respiratory Department of a tertiary referral center in central Greece between 1st of June 2021 and 1st of February 2022 were included in the present study. Results: 760 consecutive patients were included in the study; 89 (11.7%) were diagnosed with severe COVID-19 and 220 (38.7%) patients were fully vaccinated. In logistic regression, increased age (aOR = 1.12, p < 0.001), male gender (aOR = 2.29, p = 0.013) and vaccination against SARS-CoV-2 virus (aOR = 0.2, p < 0.001) were associated with mortality attributed to COVID-19 with a statistically significant association. Moreover, increased age (aOR = 1.09, p < 0.001), male gender (aOR = 1.92, p = 0.025) and vaccination against SARS-CoV-2 virus (aOR = 0.25, p < 0.001) were statistically significantly associated with clinical severity of COVID-19 infection. However, when comparing the length of hospitalization between vaccinated and unvaccinated patients, the difference was not statistically significant between the two groups (p = 0.138). Conclusions: Vaccination against SARS-CoV-2 virus had a protective effect in terms of mortality and clinical severity of COVID-19 during the fourth wave of the pandemic in Central Greece. The national vaccination policy has to focus on vulnerable populations that are expected to benefit the most from the vaccine’s protection.

COVID-19 vaccination hesitancy in Italian healthcare workers: a systematic review and meta-analysis

INTRODUCTION

As for other vaccines, vaccination hesitancy may be a determining factor in the success (or otherwise) of the COVID-19 immunization campaign in healthcare workers (HCWs).

AREAS COVERED

To estimate the proportion of HCWs in Italy who expressed COVID-19 vaccine hesitancy, we conducted a systematic review of the relevant literature and a meta-analysis. Determinants of vaccine compliance and options suggested by these studies to address vaccine hesitancy among HCWs were also analyzed. Seventeen studies were included in the meta-analysis and systematic review, selected from scientific articles available in the MEDLINE/PubMed, Google Scholar and Scopus databases between January 1, 2020 and January 25, 2022. The vaccine hesitancy rate among HCWs was 13.1% (95%CI: 6.9-20.9%). The vaccine hesitancy rate among HCWs investigated before and during the vaccination campaign was 18.2% (95%CI=12.8-24.2%) and 8.9% (95%CI=3.4-16.6%), respectively. That main reasons for vaccine hesitation were lack of information about vaccination, opinion that the vaccine is unsafe, and fear of adverse events.

EXPERT OPINION

Despite strategies to achieve a greater willingness to immunize in this category, mandatory vaccination appears to be one of the most important measures that can guarantee the protection of HCWs and the patients they care for.

SARS-CoV-2 mRNA vaccine effectiveness in healthcare workers by dosing interval and time since vaccination: test negative design, British Columbia, Canada

Background

One- and two-dose mRNA vaccine effectiveness (VE) estimates against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by dosing interval and time since vaccination were assessed among healthcare workers (HCWs) in publicly funded acute and community (nonresidential) healthcare facilities in British Columbia, Canada.

Methods

A test-negative design was used with controls matched to cases (6:1) on epidemiological week of SARS-CoV-2 test date. mRNA vaccination was defined by receipt of the first dose ≥21 days or second dose ≥14 days before the test date. HCWs ≥18 years old tested for SARS-CoV-2 between epi-weeks 3 and 39 (January 17–October 2, 2021) were included, when varying dosing intervals and a mix of circulating variants of concern contributed, including Delta dominance provincially from epi-week 31 (August 1).

Results

Single- and two-dose analyses included 1265 and 1246 cases, respectively. The median follow-up period (interquartile range) was 49 (34–69) days for single-dose and 89 (61–123) days for two-dose recipients, with 12%, 31%, and 58% of second doses given 3–5, 6, or ≥7 weeks after the first. Adjusted mRNA VE against SARS-CoV-2 was 71% (95% CI, 66%–76%) for one dose and 90% (95% CI, 88%–92%) for two doses, similar to two heterologous mRNA doses (92%; 95% CI, 86%–95%). Two-dose VE remained >80% at ≥28 weeks post–second dose. Two-dose VE was consistently 5%–7% higher with a ≥7-week vs 3–5-week interval between doses, but with overlapping confidence intervals.

Conclusions

Among HCWs, we report substantial single-dose and strong and sustained two-dose mRNA vaccine protection, with the latter maintained for at least 7 months. These findings support a longer interval between doses, with global health and equity implications.

Estimation of Real-World Vaccination Effectiveness of mRNA COVID-19 Vaccines against Delta and Omicron Variants in Japan

A resurgence of COVID-19-positive cases has been observed in many countries in the latter half of 2021. The primary reasons for this resurgence are the waning immunity of vaccination after the second dose of vaccination and the changes in public behavior due to temporal convergence. The vaccination effectiveness for the omicron and delta variants has been reported from some countries, but it is still unclear for several other regions worldwide. Here, we numerically derived the effectiveness of vaccination for infection protection in individuals and populations against viral variants for the entire Japanese population (126 million). The waning immunity of vaccination for the delta variant of Japanese individuals was 93.8% (95% CI: 93.1−94.6%) among individuals <65 years of age and 95.0% (95% CI: 95.6−96.9%) among individuals ≥65 years of age. We found that waning immunity of vaccination in individuals >65 years of age was lower than in those <65 years of age, which may be attributable to human behavior and a higher vaccination rate among individuals >65 years of age. From the reported data of 25,187 positive cases with confirmed omicron variant in Tokyo in January 2022, the effectiveness of vaccination was also estimated at 62.1% (95% CI: 48−66%) compared to that of the delta variant. Derived effectiveness of vaccination would be useful to discuss the vaccination strategy for the booster shot, as well as the status of herd immunity.

COVID-19 Infection in Children and Infants: Current Status on Therapies and Vaccines

Since the beginning in December 2019, the SARS-CoV-2 outbreak appeared to affect mostly the adult population, sparing the vast majority of children who only showed mild symptoms. The purpose of this investigation is to assess the status on the mechanisms that give children and infants this variation in epidemiology compared to the adult population and its impact on therapies and vaccines that are aimed towards them. A literature review, including in vitro studies, reviews, published guidelines and clinical trials was performed. Clinical trials concerned topics that allowed a descriptive synthesis to be produced. Four underlying mechanisms were found that may play a key role in providing COVID-19 protection in babies. No guidelines are available yet for therapy due to insufficient data; support therapy remains the most used. Only two vaccines are approved by the World Health Organization to be used in children from 12 years of age, and there are currently no efficacy or safety data for children below the age of 12 years. The COVID-19 clinical frame infection is milder in children and adolescents. This section of the population can act as vectors and reservoirs and play a key role in the transmission of the infection; therefore, vaccines are paramount. More evidence is required to guide safely the vaccination campaign.

Comparison of Neutralizing Antibody Responses at 6 Months Post Vaccination with BNT162b2 and AZD1222

Along with their level of protection against COVID-19, SARS-CoV-2-specific antibodies decline over time following vaccination with BNT162b2. However, relevant data on AZD1222 are scarce. In this context, the aim of this study was to compare SARS-CoV-2 neutralizing antibody (NAb) levels at one, three and six months after second vaccination with the BNT162b2 mRNA vaccine and the ChAdOx1 (AZD1222) viral vector vaccine (NCT04743388). The measurements were performed with the GenScript’s cPassTM SARS-CoV-2 NAbs Detection Kit (GenScript, Inc.; Piscataway, NJ, USA). Overall, data from 282 individuals were included (BNT162b2 n = 83, AZD1222 n = 199). Both vaccines induced strong NAbs responses at 1 month following vaccination. Interestingly, NAb activity seemed superior with BNT162b2 compared with AZD1222. A gradual decline in NAbs titers was evident at 3 and 6 months post vaccination with both vaccines. However, the superiority of NAb response with BNT162b2 over AZD1222 remained consistent at all time points examined. Furthermore, the elimination rate of the NAb titer was higher throughout during the study period for those vaccinated with AZD1222 compared with BNT162b2. Age, gender, body mass index or comorbidities did not have a significant impact on NAbs levels over time. Our results may inform public health policies regarding the timing of booster COVID-19 vaccine shots.

Anti-Spike SARS-CoV-2 IgG Assessment with a Commercial Assay during a 4-Month Course after COVID-19 Vaccination

We intended to assess the humoral response induced by the Pfizer/BioNTech Comirnaty COVID-19 vaccine with commercially available immunoassays: anti-spike (S) IgG and IgM, and anti-nucleocapsid (N) IgG antibodies, over a 4-month course. One hundred subjects, including 15 COVID-19 convalescents, comprised the study cohort. The SARS-CoV-2 antibodies concentrations were measured on day 0' and 10', 20', 30', 60', 90', and 120' after the first dose administration. Over the course of the study, 100% of the participants developed and sustained anti-SARS-CoV-2 S IgG antibodies. The highest concentration, exceeding the quantification range of the test (2080 BAU/mL), was reached by 67% of the subjects on day 30'. The concentration of the antibodies remained stable between days 30' and 90' but was followed by a significant decrease between days 90' and 120'. The stronger and more persistent humoral response was noted for women. The COVID-19 convalescents developed higher antibody levels, particularly 10 days after the first Comirnaty dose. Twenty-three out of the eighty-five naïve vaccinees failed to develop a detectable IgM response. LIAISON® SARS-CoV-2 TrimericS IgG (DiaSorin S.p.A, Saluggia, Italy) may be useful in the assessment of the humoral response to the Comirnaty vaccine. In contrast, Abbott's anti-S SARS-CoV-2 IgM has a limited utility in this context.