BNT162b2 Vaccine Booster and Mortality Due to Covid-19

"Going vaccine hunting": Multilevel influences on COVID-19 vaccination among racialized sexual and gender minority adults-a qualitative study

High levels of COVID-19 vaccine hesitancy have been reported among Black and Latinx populations, with lower vaccination coverage among racialized versus White sexual and gender minorities. We examined multilevel contexts that influence COVID-19 vaccine uptake, barriers to vaccination, and vaccine hesitancy among predominantly racialized sexual and gender minority individuals. Semi-structured online interviews explored perspectives and experiences around COVID-19 vaccination. Interviews were recorded, transcribed, uploaded into ATLAS.ti, and reviewed using thematic analysis. Among 40 participants (mean age, 29.0 years [SD, 9.6]), all identified as sexual and/or gender minority, 82.5% of whom were racialized. COVID-19 vaccination experiences were dominated by structural barriers: systemic racism, transphobia and homophobia in healthcare and government/public health institutions; limited availability of vaccination/appointments in vulnerable neighborhoods; absence of culturally-tailored and multi-language information; lack of digital/internet access; and prohibitive indirect costs of vaccination. Vaccine hesitancy reflected in uncertainties about a novel vaccine amid conflicting information and institutional mistrust was integrally linked to structural factors. Findings suggest that the uncritical application of "vaccine hesitancy" to unilaterally explain undervaccination among marginalized populations risks conflating structural and institutional barriers with individual-level psychological factors, in effect placing the onus on those most disenfranchised to overcome societal and institutional processes of marginalization. Rather, disaggregating structural determinants of vaccination availability, access, and institutional stigma and mistrust from individual attitudes and decision-making that reflect vaccine hesitancy, may support 1) evidence-informed interventions to mitigate structural barriers in access to vaccination, and 2) culturally-informed approaches to address decisional ambivalence in the context of structural homophobia, transphobia, and racism.

Healthcare workers' willingness to receive COVID-19 booster dose and associated factors in the Democratic Republic of the Congo

The COVID-19 booster dose is considered an important adjunct for the control of the COVID-19 pandemic due to reports of reduced immunity in fully vaccinated individuals. The aims of this study were to assess healthcare workers' intention to receive the booster dose of COVID-19 vaccine and to identify predictive factors among healthcare workers. A cross-sectional study was conducted among healthcare workers selected in two provinces, Kasai Oriental, and Haut-Lomami. Data were collected using a questionnaire administered through structured face-to-face interviews, with respondents using a pre-tested questionnaire set up on the Open Data Kit (ODK Collect). All data were analyzed using SPSS v26.0 (IBM Corporation, Armonk, NY, USA). Vaccination coverage for COVID-19, considering declarations by health workers, is around 85.9% for the province of Kasai Oriental and 85.8% for Haut-Lomami. A total of 975 responses were collected, 71.4% of health workers at Kasai Oriental and 66.4% from Haut-Lomami declared a definite willingness to receive a COVID-19 vaccine booster. The duration of protection was the main reason for accepting a booster COVID-19 dose for 64.6% of the respondents. Logistic regression analysis showed that having chronic diseases (aOR = 2.95 [1.65-5.28]), having already received one of the COVID-19 vaccines (aOR = 2.72 [1.43-5. 19]); the belief that only high-risk individuals, such as healthcare professionals and elderly people suffering from other illnesses, needed a booster dose (aOR = 1.75 [1.10-2.81]). Considering the burden of COVID-19, a high acceptance rate for booster doses could be essential to control the pandemic. Our results are novel and could help policymakers design and implement specific COVID-19 vaccination programs to reduce reluctance to seek booster vaccination.

Public Health and Economic Impact of Periodic COVID-19 Vaccination with BNT162b2 for Old Adults and High-Risk Patients in an Illustrative Prefecture of Japan: A Budget Impact Analysis

INTRODUCTION

Japan will be transitioning from the free-of-charge COVID-19 vaccination program to annual periodic vaccination under a national immunization program for old adults and high-risk patients from 2024 fall/winter season. The policy transition including out-of-pocket payment requirement may discourage vaccination, leading to a lower vaccination rate. This study aimed to estimate the impact of varying vaccination rates with BNT162b2 COVID-19 mRNA vaccine on economics and public health in an illustrative prefecture which administers and promotes the periodic vaccination program, using budget impact analysis.

METHODS

A combined cohort Markov decision tree model estimated the public health outcomes of COVID-19-related symptomatic cases, hospitalizations and deaths; and the economic outcomes including vaccine-related cost, non-vaccine-related medical cost, and productivity loss from the societal perspective. The base case examined the impact on the outcomes when vaccination coverage changed from the reference value of 50% to upper and lower values, respectively. Scenario analyses were performed based on multiple scenarios.

RESULTS

Increase in the vaccination rate demonstrated improvement in all public health outcomes. At 50% vaccination, the vaccine-related cost for 3 years in a prefecture was estimated at JPY 7.58 billion (USD 57.67 million), the non-vaccine-related medical cost at JPY 79.22 billion (USD 602.48 million), the productivity loss at JPY 253.11 billion (USD 1.92 billion), and the total cost at JPY 339.92 billion (USD 2.59 billion). When the vaccination rate increased to 90%, the total cost decreased by JPY 4.88 billion (USD 37.11 million) (1.4%). When the vaccination rate decreased to 10%, the total cost increased by JPY 5.73 billion (USD 43.58 million) (1.7%). Results were consistent across almost all scenario analyses.

CONCLUSIONS

Maintaining a high vaccination rate with BNT162b2 is important from both public health and economic perspectives in Japan. The findings highlight to local governments the importance of continued effort to promote vaccination.

The life cycle of vaccines evaluated by the European Medicines Agency

BACKGROUND

vaccines are complex products used in healthy populations. They should be carefully regulated, and benefits should clearly outweigh risks.

OBJECTIVES

To describe the evidence used to support benefit-risk evaluations of vaccines centrally assessed by the European Medicines Agency (EMA), and to identify if real-world data (RWD) was used throughout the vaccine life cycle.

METHODS

Cohort study of vaccines approved in the European Union. Inclusion criteria comprised having ATC code J07 and being centrally approved between 2012 and 2022. We collected data from regulatory documents, study protocols, and, when necessary, from scientific publications. Vaccines were followed from initial approval up to March 2023.

RESULTS

We included 31 vaccines addressing 17 therapeutic areas. More than 390 studies were used in the process of initial marketing authorisation (MA) and monitoring, and 174 studies were listed in initial risk management plans. We also identified 93 studies in the EU PAS register. At MA, all vaccines had at least one pivotal trial and 27 vaccines had at least one supportive study. Most pivotal trials were randomized, double-blinded and active-controlled, with immunogenicity endpoints as primary outcome. RWD was used for extension of indications and monitoring of at least 4 vaccines, and the undertaking of RWE studies was foreseen in the RMP of at least 17 vaccines.

DISCUSSION

Our study revealed an important reliance on randomized controlled trials with individual-level randomization, and a significant focus on immunogenicity endpoints. The use of RWD in vaccine assessments so far has been restricted to COVID-19, and despite its challenges and limitations, we believe that efforts to expand adoption of RWE in continuous benefit-risk assessments should be made. We further highlight the need to enhance data transparency and reporting standards since heterogeneity among regulatory documents made it difficult to identify all the studies considered in vaccine evaluations.

Hybrid immunity protection against SARS-CoV-2 and severe COVID-19 in kidney transplantation: A retrospective, comparative cohort study

Hybrid immunity, resulting from a combination of SARS-CoV-2 infection and vaccination, offers robust protection against COVID-19 in the general population. However, its impact on immunocompromised patients remains unexplored. We investigated the effect of hybrid immunity against the Omicron variant in a population of kidney transplant recipients receiving the fourth dose mRNA monovalent vaccination. By extracting data from the clinical records and performing individual interviews, participants were categorized into the hybrid cohort (previously infected and vaccinated individuals) and the vaccine cohort (vaccinated-only individuals). The study comprised 1114 participants, 442 in the hybrid and 672 in the vaccine cohorts. From April 2022 to August 2023, 286 infections, 38 hospitalizations and 9 deaths were reported. The cumulative incidence of infection was 12.1% (95% confidence interval [CI], 9.03-16.03) for the hybrid cohort and 36.54% (95% CI, 32.81-40.54) for the vaccine cohort after 300 days of follow-up. Hybrid immunity was associated to a 72% lower risk of infection (adjusted hazard ratio, 0.28; 95% CI, 0.21-0.38) and a 96% lower risk of hospitalization (adjusted hazard ratio, 0.04; 95% CI, 0.01-0.32). No deaths occurred in the hybrid cohort. Hybrid immunity was associated with a lower incidence of SARS-CoV-2 infection and severe COVID-19, underscoring its importance for risk stratification in this vulnerable patient population.

Evidence base for yearly respiratory virus vaccines: Current status and proposed improved strategies

Annual vaccination is widely recommended for influenza and SARS-CoV-2. In this essay, we analyse and question the prevailing policymaking approach to these respiratory virus vaccines, especially in the United States. Every year, licensed influenza vaccines are reformulated to include specific strains expected to dominate in the season ahead. Updated vaccines are rapidly manufactured and approved without further regulatory requirement of clinical data. Novel vaccines (i.e. new products) typically undergo clinical trials, though generally powered for clinically unimportant outcomes (e.g. lab-confirmed infections, regardless of symptomatology or antibody levels). Eventually, the current and future efficacy of influenza and COVID-19 vaccines against hospitalization or death carries considerable uncertainty. The emergence of highly transmissible SARS-CoV-2 variants and waning vaccine-induced immunity led to plummeting vaccine effectiveness, at least against symptomatic infection, and booster doses have since been widely recommended. No further randomized trials were performed for clinically important outcomes for licensed updated boosters. In both cases, annual vaccine effectiveness estimates are generated by observational research, but observational studies are particularly susceptible to confounding and bias. Well-conducted experimental studies, particularly randomized trials, are necessary to address persistent uncertainties about influenza and COVID-19 vaccines. We propose a new research framework which would render results relevant to the current or future respiratory viral seasons. We demonstrate that experimental studies are feasible by adopting a more pragmatic approach and provide strategies on how to do so. When it comes to implementing policies that seriously impact people's lives, require substantial public resources and/or rely on widespread public acceptance, high evidence standards are desirable.

The association between BNT162b2 vaccinations and incidence of immune-mediated comorbidities

BACKGROUND

A large vaccination campaign was initiated worldwide in December 2020 in order to prevent infection with SARS-CoV-2 and severe Covid-19 disease. However, long-term adverse effects of vaccination remain unclear. Therefore, our objective was to examine the association between vaccination and the incidence of autoimmune diagnoses in the first year after vaccine uptake.

METHODS

This retrospective cohort study based on Clalit Health Services (CHS) comprehensive database compared the rates of immune-mediated diagnoses among BNT162b2 vaccinated versus unvaccinated individuals. As a reference, a secondary cohort compared individuals infected with Sars-CoV-2 versus uninfected individuals. The minimum follow-up period was 4 months. The cohorts were divided into 4 age groups (12-17, 18-44, 45-64, 65 years or older). Multivariate Cox proportional hazard regression models were applied, followed by a correction for multiple comparisons using the False Discovery Rate (FDR) method, hence accounting for the investigation of multiple clinical outcomes.

RESULTS

Increased risk for immune-mediated diagnoses following vaccination with BNT162b2 was observed for psoriasis in all age groups (HR 1.41-1.69), colitis among patients younger than 65 years (HR 1.38-1.93), vitiligo in patients aged 45-64 (HR 2.82, 95 %CI: 1.57-5.08) and for polymyalgia-rheumatica in patients aged 65 years or older (HR 2.12, 95 % CI: 1.3-3.47). In the reference cohort, patients who were infected by Covid-19 were at increased risk for fibromyalgia (HR 1.72, 95 % CI: 1.36-2.19 in individuals aged 18-44; HR 1.71, 95 % CI: 1.31-2.22 in individuals aged 45-64), and hypothyroidism (HR 1.54, 95 % CI: 1.15-2.07 in individuals aged 65 years or older).

CONCLUSIONS

The BNT162b2 vaccine was associated with increased risk (though rare) for psoriasis, colitis and polymyalgia rheumatica. These findings should be considered as a part of the risk-benefit assessment when planning future vaccination programs for various population groups.

COVID-19 Booster Uptake: Are Hesitant Adopters Less Likely to Get a Booster Shot Than Nonhesitant Adopters?

The main objective of this study was to assess whether hesitancy toward receiving the initial COVID-19 vaccine was associated with uptake of the COVID-19 booster several months after it became available to all US adults. We ask whether hesitancy toward the initial COVID-19 vaccine was significantly associated with lower odds of COVID-19 booster uptake among adults. We test this association within the context of the highly rural state of Arkansas. By January 2022, the US had set a global record of nearly 1 million daily cases. The purpose of this study was to advance our understanding of vaccine hesitancy among those who have already received a dose of the COVID-19 vaccine and how that hesitancy may shape COVID-19 booster uptake. We analyzed data from a random sample survey of Arkansan adults (N = 2,201) between March 1 and March 28, 2022 and constrained our analytical sample to those who had received a vaccine (N = 1,649). Nearly two-thirds of vaccinated Arkansas residents had received a COVID-19 booster. Hesitancy was common even among vaccinated individuals and was significantly associated with reduced odds of COVID-19 booster uptake, even after controlling for other factors. Findings provide further support for conceptualizing vaccine hesitancy as an attitude related to-but separate from-the behavior of vaccination, as opposed to conflating vaccination with being nonhesitant. Public health interventions aimed at increasing COVID-19 booster uptake should pay attention to vaccine hesitancy indicated at the initiation of the series and should not ignore the vaccinated as an important population to target for intervention.

Longitudinal Assessment of BNT162b2- and mRNA-1273-Induced Anti-SARS-CoV-2 Spike IgG Levels and Avidity Following Three Doses of Vaccination

SARS-CoV-2 vaccination-induced protection against infection is likely to be affected by functional antibody features. To understand the kinetics of antibody responses in healthy individuals after primary series and third vaccine doses, sera from the recipients of the two licensed SARS-CoV-2 mRNA vaccines were assessed for circulating anti-SARS-CoV-2 spike IgG levels and avidity for up to 6 months post-primary series and 9 months after the third dose. Following primary series vaccination, anti-SARS-CoV-2 spike IgG levels declined from months 1 to 6, while avidity increased through month 6, irrespective of the vaccine received. The third dose of either vaccine increased anti-SARS-CoV-2 spike IgG levels and avidity and appeared to enhance antibody level persistence-generating a slower rate of decline in the 3 months following the third dose compared to the decline seen after the primary series alone. The third dose of both vaccines induced significant avidity increases 1 month after vaccination compared to the avidity response 6 months post-primary series vaccination (p ≤ 0.001). A significant difference in avidity responses between the two vaccines was observed 6 months post-third dose, where the BNT162b2 recipients had higher antibody avidity levels compared to the mRNA-1273 recipients (p = 0.020).

What makes SARS-CoV-2 unique? Focusing on the spike protein

Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) seriously threatens public health and safety. Genetic variants determine the expression of SARS-CoV-2 structural proteins, which are associated with enhanced transmissibility, enhanced virulence, and immune escape. Vaccination is encouraged as a public health intervention, and different types of vaccines are used worldwide. However, new variants continue to emerge, especially the Omicron complex, and the neutralizing antibody responses are diminished significantly. In this review, we outlined the uniqueness of SARS-CoV-2 from three perspectives. First, we described the detailed structure of the spike (S) protein, which is highly susceptible to mutations and contributes to the distinct infection cycle of the virus. Second, we systematically summarized the immunoglobulin G epitopes of SARS-CoV-2 and highlighted the central role of the nonconserved regions of the S protein in adaptive immune escape. Third, we provided an overview of the vaccines targeting the S protein and discussed the impact of the nonconserved regions on vaccine effectiveness. The characterization and identification of the structure and genomic organization of SARS-CoV-2 will help elucidate its mechanisms of viral mutation and infection and provide a basis for the selection of optimal treatments. The leaps in advancements regarding improved diagnosis, targeted vaccines and therapeutic remedies provide sound evidence showing that scientific understanding, research, and technology evolved at the pace of the pandemic.

Prevalence of neutralizing antibodies against SARS-CoV-2 using a rapid serological test in health workers of a Spanish Department of Health in Alicante (Spain) before the booster dose of the vaccine

AIM

To study the prevalence of neutralizing antibodies in healthcare workers and healthcare support personnel after the administration of the second dose of the BNT162b2 vaccine (Pfizer-BioNTech).

MATERIALS AND METHODS

In December 2021, we undertook a study in the Health Department in Orihuela, Alicante (Spain), which consists of 1500 workers. We collected demographic variables about the study participants, and we performed a "point-of-care" immunochromatography test to measure the presence of neutralizing antibodies (OJABIO® SARS-CoV-2 Neutralizing Antibody Detection Kit, manufactured by Wenzhou OJA Biotechnology Co., Ltd. Wenzhou, Zhejiang, China) before the administration of the third dose of the vaccine.

RESULTS

We obtained complete information about 964 (64%) workers, which consisted of 290 men and 674 women. The average age was 45,8 years (min. 18, max. 68) and the average time since the last dose of the vaccine was 40,5 weeks (min. 1,71, max. 47,71). A total of 131 participants (13,5%) had suffered infection by SARS-CoV-2 confirmed using RT-PCR. The proportion of participants who showed presence of neutralizing antibodies was 38,5%. In the multivariable analysis, the time since the last dose of the vaccine (aOR week: 1,07; 95%CI: 1,04; 1,09) and previous infection by SARS-CoV-2 (aOR: 3,7; 95CI: 2,39; 5,63) showed a statistically significant association with the presence of neutralizing antibodies.

CONCLUSIONS

The time since the administration of the last dose of the vaccine and the previous infection by SARS-CoV-2 determined the presence of neutralizing antibodies in 38,5% of the healthcare workers and support workers.

Expansion of memory Vδ2 T cells following SARS-CoV-2 vaccination revealed by temporal single-cell transcriptomics

γδ T cells provide rapid cellular immunity against pathogens. Here, we conducted matched single-cell RNA-sequencing and γδ-TCR-sequencing to delineate the molecular changes in γδ T cells during a longitudinal study following mRNA SARS-CoV-2 vaccination. While the first dose of vaccine primes Vδ2 T cells, it is the second administration that significantly boosts their immune response. Specifically, the second vaccination uncovers memory features of Vδ2 T cells, shaped by the induction of AP-1 family transcription factors and characterized by a convergent central memory signature, clonal expansion, and an enhanced effector potential. This temporally distinct effector response of Vδ2 T cells was also confirmed in vitro upon stimulation with SARS-CoV-2 spike-peptides. Indeed, the second challenge triggers a significantly higher production of IFNγ by Vδ2 T cells. Collectively, our findings suggest that mRNA SARS-CoV-2 vaccination might benefit from the establishment of long-lasting central memory Vδ2 T cells to confer protection against SARS-CoV-2 infection.

Reported effectiveness of COVID-19 monovalent booster vaccines and hybrid immunity against mild and severe Omicron disease in adults: A systematic review and meta-regression analysis

Background

Waning of COVID-19 vaccine efficacy/effectiveness (VE) has been observed across settings and epidemiological contexts. We conducted a systematic review of COVID-19 VE studies and performed a meta-regression analysis to improve understanding of determinants of waning.

Methods

Systematic review of PubMed, medRxiv and the WHO-International Vaccine Access Center database summarizing VE studies on 31 December 2022. Studies were those presenting primary adult VE data from hybrid immunity or third/fourth mRNA COVID-19 monovalent vaccine doses [due to limited data with other vaccines] against Omicron, compared with unvaccinated individuals or individuals eligible for corresponding booster doses but who did not receive them. We used meta-regression models, adjusting for confounders, with weeks since vaccination as a restricted cubic spline, to estimate VE over time since vaccination.

Results

We identified 55 eligible studies reporting 269 VE estimates. Most estimates (180/269; 67 %) described effectiveness of third dose vaccination; with 48 (18 %) and 41 (15 %) describing hybrid immunity and fourth dose effectiveness, respectively, mostly (200; 74 %) derived from test-negative design studies. Most estimates (176/269; 65 %) reported VE compared with unvaccinated comparison groups. Estimated VE against mild outcomes declined following third dose vaccination from 62 % (95 % CI: 58 % - 66 %) after 4 weeks to 48 % (41 % - 55 %) after 20 weeks. Fourth dose VE against mild COVID-19 declined from 48 % (41 % - 56 %) after 4 weeks to 47 % (19 % - 65 %) after 20 weeks. VE for severe outcomes was higher and declined in the three-dose group from 90 % (87 % - 92 %) after 4 weeks to 70 % (65 - 74 %) after 20 weeks.

Conclusions

Time-since vaccination is an important determinant of booster dose VE, a finding which may support seasonal COVID-19 booster doses. Integration of VE and immunological parameters - and longer-term data including from other vaccine types - are needed to better-understand determinants of clinical protection.

Persistence in risk and effect of COVID-19 vaccination on long-term health consequences after SARS-CoV-2 infection

The persisting risk of long-term health consequences of SARS-CoV-2 infection and the protection against such risk conferred by COVID-19 vaccination remains unclear. Here we conducted a retrospective territory-wide cohort study on 1,175,277 patients with SARS-CoV-2 infection stratified by their vaccination status and non-infected controls to evaluate the risk of clinical sequelae, cardiovascular and all-cause mortality using a territory-wide public healthcare database with population-based vaccination records in Hong Kong. A progressive reduction in risk of all-cause mortality was observed over one year between patients with SARS-CoV-2 infection and controls. Patients with complete vaccination or have received booster dose incurred a lower risk of health consequences including major cardiovascular diseases, and all-cause mortality than unvaccinated or patients with incomplete vaccination 30-90 days after infection. Completely vaccinated and patients with booster dose of vaccines did not incur significant higher risk of health consequences from 271 and 91 days of infection onwards, respectively, whilst un-vaccinated and incompletely vaccinated patients continued to incur a greater risk of clinical sequelae for up to a year following SARS-CoV-2 infection. This study provided real-world evidence supporting the effectiveness of COVID-19 vaccines in reducing the risk of long-term health consequences of SARS-CoV-2 infection and its persistence following infection.

Pneumonia Prevalence Upon Chest Radiography According to Vaccination Status Among Patients Under 50 Years of Age With Coronavirus Disease 2019

BACKGROUND

Coronavirus disease 2019 (COVID-19) vaccination is effective in preventing the disease transmission and progression. However, the relatively mild disease course of the omicron variant and the decrease in antibodies over time after vaccination raise questions about the effectiveness of vaccination, especially in young people. We compared the prevalence of pneumonia and chest X-ray severity score according to vaccination status among patients < 50 years old with COVID-19.

METHODS

From January 17 to March 17, 2022, 579 patients with COVID-19, who were < 50 years old and had a known vaccination history in our institution, were all included in this study. All patients underwent initial chest radiography, and follow-up chest radiographs were obtained every two days until discharge. Pneumonia was scored from the radiographs using the Brixia scoring system. The scores of the six lung zones were added for a total score ranging from 0 to 18. Patients were divided into four groups according to 10-year age intervals. Differences between groups were analyzed using the χ² or Fisher's exact tests for categorical variables and the Kruskal-Wallis test or analysis of variance for continuous variables.

RESULTS

Among patients aged 12-19 years, the prevalence of pneumonia did not differ depending on vaccination status (non-vaccinated vs. vaccinated, 1/47 [2.1%] vs. 1/18 [5.6%]; P = 0.577). Among patients in their 20s, the prevalence of pneumonia was significantly higher among non-vaccinated patients than among vaccinated patients (8/28, 28.6% vs. 7/138, 5.1%, P < 0.001), similar to patients in their 40s (32/52 [61.5%] vs. 18/138 [13.0%]; P < 0.001). The chest X-ray severity score was also significantly higher in non-vaccinated patients than that in vaccinated patients in their 20s to their 40s (P < 0.001), but not among patients aged 12-19 years (P = 0.678).

CONCLUSION

In patients aged 20-49 years, vaccinated patients had a significantly lower prevalence of pneumonia and chest X-ray severity score than non-vaccinated patients.

The importance of falsification endpoints in observational studies of vaccination to prevent severe disease: A critique of a harm-benefit analysis of BNT162b2 vaccination of 5- to 11-year-olds

We explore one systematic review and meta-analysis of both observational and randomized studies examining COVID-19 vaccines in 5- to 11-year-olds, which reported substantial benefits associated with vaccinating this age group. We discuss the limitations of the individual studies that were used to estimate vaccination benefits. The review included five observational studies that evaluated vaccine effectiveness (VE) against COVID-19 severe disease or hospitalization. All five studies failed to adequately assess differences in underlying health between vaccination groups. In terms of vaccination harms, looking only at the randomized studies, a significantly higher odds of adverse events was identified among the vaccinated compared with the unvaccinated. Observational studies are at risk of overestimating the effectiveness of vaccines against severe disease if healthy vaccinee bias is present. Falsification endpoints can provide valuable information about underlying healthy vaccinee bias. Studies that have not adequately ruled out bias due to better health among the vaccinated or more vaccinated should be viewed as unreliable for estimating the VE of COVID-19 vaccination against severe disease and mortality. Existing systematic reviews that include observational studies of the COVID-19 vaccine in children may have overstated or falsely inferred vaccine benefits due to unidentified or undisclosed healthy vaccinee bias.

Significant Publications on Infectious Diseases Pharmacotherapy in 2021

Purpose: To summarize the most noteworthy infectious diseases (ID) pharmacotherapy articles published in peer-reviewed literature in 2021. Summary: Members of the Houston Infectious Diseases Network (HIDN) nominated articles that were deemed to have significant contributions to ID pharmacotherapy in 2021. These nominations included articles pertaining to both general ID, including coronavirus disease 2019 (COVID-19), and human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) pharmacotherapy. A total of 35 articles were nominated by HIDN: 30 articles pertaining to general ID pharmacotherapy and 5 articles with HIV/AIDS focus. To select the most influential articles of 2021, a survey was created and distributed to members of the Society of Infectious Diseases Pharmacists (SIDP). Of the 239 SIDP members who responded to the survey, there were 192 recorded votes for the top 10 general ID pharmacotherapy articles and 47 recorded votes for the top HIV/AIDS article, respectively. The top publications are summarized. Conclusion: Antimicrobial stewardship and the optimal management of infectious disease states continues to be a priority in the midst of the ongoing coronavirus disease 2019 (COVID-19) global pandemic. In light of the sheer volume of ID-related articles published in the past year, this review aims to aid clinicians in remaining up-to-date on key practice-changing ID pharmacotherapy publications from 2021.

Effectiveness of nirmatrelvir-ritonavir on severe outcomes of COVID-19 in the era of vaccination and Omicron: An updated meta-analysis

Nirmatrelvir-ritonavir (NR) was approved to treat SARS-CoV-2 positive outpatients at high risk of progression to severe disease, based on a randomized trial in unvaccinated patients. Effectiveness in vaccinated patients and against Omicron has not yet been confirmed by clinical trial data, but a recent meta-analysis suggested good real-world effectiveness based on 12 studies. We updated this meta-analysis by searching Medline and Embase databases for studies assessing effectiveness of NR on mortality, hospitalization, composite outcome of hospitalization and/or death, and progression to severe disease, published between October 1, 2022 and May 22, 2023. Random effects meta-analysis and subgroup analysis for vaccinated patients was performed. A total of 32 studies were included in the meta-analysis. Pooled RR for the effect of NR on mortality, hospitalization, hospitalization and/or mortality, and progression to severe disease were 0.36 (95% confidence interval [CI]: 0.25-0.52), 0.43 (CI: 0.37-0.51), 0.52 (CI: 0.45-0.61) and 0.54 (CI: 0.41-0.73), respectively. A subgroup analysis on vaccinated patients indicated lower effectiveness of NR on mortality (RR: 0.55, CI: 0.45-0.68), but similar effectiveness for hospitalization, hospitalization and/or mortality, or progression to severe disease (RR: 0.52, 0.58, and 0.66, respectively). This updated meta-analysis robustly confirms the protective effects of NR on severe COVID-19 outcomes.

Genetic characteristics involved in COVID-19 severity. The CARGENCORS case-control study and meta-analysis

Pre-existing coronary artery disease (CAD), and thrombotic, inflammatory, or virus infectivity response phenomena have been associated with COVID-19 disease severity. However, the association of candidate single nucleotide variants (SNVs) related to mechanisms of COVID-19 complications has been seldom analysed. Our aim was to test and validate the effect of candidate SNVs on COVID-19 severity. CARGENCORS (CARdiovascular GENetic risk score for Risk Stratification of patients positive for SARS-CoV-2 [COVID-19] virus) is an age- and sex-matched case-control study with 818 COVID-19 cases hospitalized with hypoxemia, and 1636 controls with COVID-19 treated at home. The association between severity and SNVs related to CAD (n = 32), inflammation (n = 19), thrombosis (n = 14), virus infectivity (n = 11), and two published to be related to COVID-19 severity was tested with adjusted logistic regression models. Two external independent cohorts were used for meta-analysis (SCOURGE and UK Biobank). After adjustment for potential confounders, 14 new SNVs were associated with COVID-19 severity in the CARGENCORS Study. These SNVs were related to CAD (n = 10), thrombosis (n = 2), and inflammation (n = 2). We also confirmed eight SNVs previously related to severe COVID-19 and virus infectivity. The meta-analysis showed five SNVs associated with severe COVID-19 in adjusted analyses (rs11385942, rs1561198, rs6632704, rs6629110, and rs12329760). We identified 14 novel SNVs and confirmed eight previously related to COVID-19 severity in the CARGENCORS data. In the meta-analysis, five SNVs were significantly associated to COVID-19 severity, one of them previously related to CAD.

Glucose control during breakthrough SARS-CoV-2 infections in vaccinated patients with type 1 diabetes

AIMS

This study aims at evaluating the trend of glycemic control metrics during the infection of SARS-CoV-2 in individuals with Type 1 Diabetes (T1D) using a Continuous Glucose Monitoring (CGM) system and vaccinated against COVID-19.

MATERIALS AND METHODS

This is a retrospective study of T1D subjects who got a breakthrough SARS-CoV-2 infection between November 2021 and February 2022. Data of glycemic control of CGM-derived metrics were compared 14 days before COVID-19 (Time 1), 14 days during COVID-19 (Time 2) and 14 days after COVID-19 (Time 3).

RESULTS

A total of 106 patients with T1D and breakthrough SARS-CoV-2 infection was included in the analysis. A significant reduction of GMI [%, 7.41 ± 1.60 vs 7.52 ± 1.63, P = 0.006)] and increase of TIR [%, 54.6 ± 20.4 vs 52.1 ± 19.7, P = 0.026] were observed at Time 3 as compared with Time 2. There was a significant reduction of SD (P < 0.001) and CV (P < 0.001) at Time 3 and Time 2 as compared with Time 1, associated with significant changes of mean glucose levels, TBR level 1 and total daily insulin doses.

CONCLUSIONS

Breakthrough SARS-CoV-2 infection did not worsen glycemic control in vaccinated people with T1D.

Vaccinating against a Novel Pathogen: A Critical Review of COVID-19 Vaccine Effectiveness Evidence

We study the experience with COVID-19 vaccination of an initially naïve population, which can inform planning for vaccination against the next novel, highly transmissible pathogen. We focus on the first two pandemic years (wild strain through Delta), because after the Omicron wave in early 2022, very few people were still SARS-CoV-2-naïve. Almost all were vaccinated, infected, or often both. We review the evidence on COVID-19 vaccine effectiveness (VE) and waning effectiveness over time and the relative effectiveness of the four principal vaccines used in developed Western countries: BNT162b2 (Pfizer-BioNTech), mRNA1273 (Moderna), Ad26.CoV2.S (Johnson&Johnson), and ChAdOx1-S (AstraZeneca). As a basis for our analysis, we conducted a PRISMA-compliant review of all studies on PubMed through 15 August 2022, reporting VE against four endpoints for these four vaccines: any infection, symptomatic infection, hospitalization, and death. The mRNA vaccines (BNT162b2, mRNA1273) had high initial VE against all endpoints but protection waned after approximately six months, with BNT162b2 declining faster than mRNA1273. Both mRNA vaccines outperformed the viral vector vaccines (Ad26.CoV2.S and ChAdOx1-S). A third "booster" dose, roughly six months after the initial doses, substantially reduced symptomatic infection, hospitalization, and death. In hindsight, a third dose should be seen as part of the normal vaccination schedule. Our analysis highlights the importance of the real-time population-level surveillance needed to assess evidence for waning, and the need for rapid regulatory response to this evidence.

Evidence synthesis and pooled analysis of vaccine effectiveness for COVID-19 mRNA vaccine BNT162b2 as a heterologous booster after inactivated SARS-CoV-2 virus vaccines

Introduction of primary COVID-19 vaccination has helped reduce severe disease and death caused by SARS-CoV-2 infection. Understanding the protection conferred by heterologous booster regimens informs alternative vaccination strategies that enable programmatic resilience and can catalyze vaccine confidence and coverage. Inactivated SARS-CoV-2 vaccines are among the most widely used vaccines worldwide. This review synthesizes the available evidence identified as of May 26, 2022, on the safety, immunogenicity, and effectiveness of a heterologous BNT162b2 (Pfizer-BioNTech) mRNA vaccine booster dose after an inactivated SARS-CoV-2 vaccine primary series, to help protect against COVID-19. Evidence showed that the heterologous BNT16b2 mRNA vaccine booster enhances immunogenicity and improves vaccine effectiveness against COVID-19, and no new safety concerns were identified with heterologous inactivated primary series with mRNA booster combinations.

Design and analysis heterogeneity in observational studies of COVID-19 booster effectiveness: A review and case study

We investigated the design and analysis of observational booster vaccine effectiveness (VE) studies by performing a scoping review of booster VE literature with a focus on study design and analytic choices. We then applied 20 different approaches, including those found in the literature, to a single dataset from Michigan Medicine. We identified 80 studies in our review, including over 150 million observations in total. We found that while protection against infection is variable and dependent on several factors including the study population and time period, both monovalent boosters and particularly the bivalent booster offer strong protection against severe COVID-19. In addition, VE analyses with a severe disease outcome (hospitalization, intensive care unit admission, or death) appear to be more robust to design and analytic choices than an infection endpoint. In terms of design choices, we found that test-negative designs and their variants may offer advantages in statistical efficiency compared to cohort designs.

Covid-19 Vaccine Hesitancy and Under-Vaccination among Marginalized Populations in the United States and Canada: A Scoping Review

BACKGROUND

Amid persistent disparities in Covid-19 vaccination and burgeoning research on vaccine hesitancy (VH), we conducted a scoping review to identify multilevel determinants of Covid-19 VH and under-vaccination among marginalized populations in the U.S. and Canada.

METHODS

Using the scoping review methodology developed by the Joanna Briggs Institute, we designed a search string and explored 7 databases to identify peer-reviewed articles published from January 1, 2020-October 25, 2022. We combine frequency analysis and narrative synthesis to describe factors influencing Covid-19 VH and under-vaccination among marginalized populations.

RESULTS

The search captured 11,374 non-duplicated records, scoped to 103 peer-reviewed articles. Among 14 marginalized populations identified, African American/Black, Latinx, LGBTQ+, American Indian/Indigenous, people with disabilities, and justice-involved people were the predominant focus. Thirty-two factors emerged as influencing Covid-19 VH, with structural racism/stigma and institutional mistrust (structural)(n = 71) most prevalent, followed by vaccine safety (vaccine-specific)(n = 62), side effects (vaccine-specific)(n = 50), trust in individual healthcare provider (social/community)(n = 38), and perceived risk of infection (individual)(n = 33). Structural factors predominated across populations, including structural racism/stigma and institutional mistrust, barriers to Covid-19 vaccine access due to limited supply/availability, distance/lack of transportation, no/low paid sick days, low internet/digital technology access, and lack of culturally- and linguistically-appropriate information.

DISCUSSION

We identified multilevel and complex drivers of Covid-19 under-vaccination among marginalized populations. Distinguishing vaccine-specific, individual, and social/community factors that may fuel decisional ambivalence, more appropriately defined as VH, from structural racism/structural stigma and systemic/institutional barriers to vaccination access may better support evidence-informed interventions to promote equity in access to vaccines and informed decision-making among marginalized populations.

Anti-SARS-CoV-2 Antibody Testing: Role and Indications

Since the onset of the COVID-19 pandemic in March 2020, over 769 million confirmed COVID-19 cases, including close to 7 million COVID-19-related deaths, have been reported. Although mortality rates have dropped notably compared to the first months of the pandemic, spikes in reported cases and mortality rates continue to be registered. Both recent spikes in case numbers and the continued emergence of new variants suggest that vulnerable patient groups, including older adults, immunocompromised patients, and patients with severe comorbidities, are going to continue to be affected by COVID-19. In order to curb the pandemic, relieve the pressure on primary care facilities, and reduce mortality rates, global vaccination programs have been established by the WHO, with over 13.5 billion vaccine doses having been administered globally. In most immunocompetent individuals, vaccination against COVID-19 results in the production of anti-SARS-CoV-2 spike antibodies. However, certain patient subsets have inadequate or reduced immune responses, and immune responses are known to decrease with age. General recommendations on the timing of booster vaccinations may therefore be insufficient to protect vulnerable patients. This review aims to evaluate the clinical role of anti-SARS-CoV-2 antibodies, focusing on measurement indications, prognostic value, and potential as a correlate of protection to guide future booster vaccination strategies.

Residential Segregation and County-Level COVID-19 Booster Coverage in the Deep South: Surveillance Report and Ecological Study

BACKGROUND

COVID-19 had a greater impact in the Deep South compared with other regions in the United States. While vaccination remains a top priority for all eligible individuals, data regarding the progress of booster coverage in the Deep South and how the coverage varies by county and age are sparse. Despite existing evidence of racial and ethnic disparities in COVID-19 vaccinations at the individual level, there is an urgent need for evidence at the population level. Such information could highlight vulnerable communities and guide future health care policy-making and resource allocation.

OBJECTIVE

We aimed to evaluate county-level COVID-19 booster coverage by age group in the Deep South and explore its association with residential segregation.

METHODS

An ecological study was conducted at the population level by integrating COVID-19 vaccine surveillance data, residential segregation index, and county-level factors across the 418 counties of 5 Deep South states from December 15, 2021, to October 19, 2022. We analyzed the cumulative percentages of county-level COVID-19 booster uptake by age group (eg, 12 to 17 years, 18 to 64 years, and at least 65 years) by the end of the study period. The longitudinal relationships were examined between residential segregation, the interaction of time and residential segregation, and COVID-19 booster coverage using the Poisson model.

RESULTS

As of October 19, 2022, among the 418 counties, the median of booster uptake was 40% (IQR 37.8%-43%). Compared with older adults (ie, at least 65 years; median 63.1%, IQR 59.5%-66.5%), youth (ie, 12 to 17 years; median 14.1%, IQR 11.3%-17.4%) and adults (ie, 18 to 64 years; median 33.4%, IQR 30.5%-36.5%) had lower percentages of booster uptake. There was geospatial heterogeneity in the county-level COVID-19 booster coverage. We found that higher segregated counties had lower percentages of booster coverage. Such relationships attenuated as time increased. The findings were consistent across the age groups.

CONCLUSIONS

The progress of county-level COVID-19 booster coverage in the Deep South was slow and varied by age group. Residential segregation precluded the county-level COVID-19 booster coverage across age groups. Future efforts regarding vaccination strategies should focus on youth and adults. Health care facilities and resources are needed in racial and ethnic minority communities.

Lessons from the COVID-19 pandemic: Mortality impacts in Poland versus European Union

With COVID-19 moving toward an endemic phase, it is worthwhile to identify lessons from the pandemic that can promote the effective strengthening of national health systems. We look at a single country, Poland, and compare it with the European Union (EU) to contrast approaches and outcomes. Among possible relevant indices, we examine characteristics of COVID-19-related mortality and excess all-cause mortality from March 2020 to February 2022. We demonstrate that both the numbers of COVID-related deaths and all-cause deaths in Poland were much higher than the EU average for most months in the study period. We juxtapose the percentage of fully vaccinated population and cumulative COVID-19 deaths per million people for EU Member States and show that typically higher vaccination rates are accompanied by lower mortality. We also show that, in addition to medical science, the use of a risk science toolbox would have been valuable in the management of the COVID-19 pandemic in Poland. Better and more widespread understanding of risk perception of the pandemic and the COVID-19 vaccines would have improved managing vaccine hesitancy, potentially leading to more effective pro-vaccination measures.

Trends in the COVID-19 Pandemic in Italy during the Summers of 2020 (before Mass Vaccination), 2021 (after Primary Mass Vaccination) and 2022 (after Booster Mass Vaccination): A Real-World Nationwide Study Based on a Population of 58.85 Million People

Like all RNA viruses, SARS-CoV-2 shows a high mutation rate, which has led to the emergence of new variants. Among them, Gamma and Delta developed at the turn of 2020-2021 in Amazonas and India, two ecoregions characterized by hot-humid weather, very similar to that of the summer season in Italy due to climate change, the first Western country to be hit hard by COVID-19 and to experience lockdown restrictions in a democratic framework of 58.85 million people. The aim of our research has been to evaluate the impact of climate on the COVID-19 pandemic in Italy during the summers of 2020 (before mass vaccination), 2021 (after primary mass vaccination) and 2022 (after booster mass vaccination), also taking into account the emergence of these two variants.

METHODS

During the state of national health emergency and the Draghi government, the Civil Defense Department released the aggregate data coming from the Ministry of Health, the Higher Institute of Health, the Independent Provinces and the Italian Regions daily, in order to inform about the pandemic situation in Italy. Among these data there were the number of deaths, hospitalizations in intensive care units (ICU), non-ICU patients, contagions and performed swabs. By means of a team effort, we have collected and elaborated all these data, comparing the COVID-19 pandemic in Italy during the summers of 2020 (following the nationwide lockdown), 2021 and 2022.

RESULTS

from the summer of 2020 to the summers of 2021 and 2022 all pandemic trend indicators have shown a sharp worsening in Italy. COVID-19 deaths increased by ≈298% and ≈834%, ICU hospitalizations by ≈386% and ≈310%, non-ICU hospitalizations by ≈224% and ≈600%, contagions by ≈627% and ≈6850% (i.e., ≈68.50 times), swabs by ≈354% and ≈370%, and the mean positivity rate passed from ≈1% to ≈2% and ≈20%, respectively.

CONCLUSIONS

SARS-CoV-2 can be transmitted in any climate, including areas with hot and humid weather, and the emergence of variants adapted to hot-humid climates may result in summer COVID-19 outbreaks, even in neither tropical nor subtropical countries. Although COVID-19 vaccines can confer cross-protection against newly emerging variants, this cross-immunity is naturally not absolute but limited, considering that vaccine protection wanes significantly after 6 months. It follows that a subject vaccinated at the beginning of the winter will not be completely covered in the height of the summer, and we should not forget the unvaccinated. As a final remark, the long and strict nationwide lockdown made it possible to flatten SARS-CoV-2 circulation and, therefore, its negative impact on Italy during the summer of 2020.

Dynamics of Serum-Neutralizing Antibody Responses in Vaccinees through Multiple Doses of the BNT162b2 Vaccine

SARS-CoV-2 mRNA vaccines are administered as effective prophylactic measures for reducing virus transmission rates and disease severity. To enhance the durability of post-vaccination immunity and combat SARS-CoV-2 variants, boosters have been administered to two-dose vaccinees. However, long-term humoral responses following booster vaccination are not well characterized. A 16-member cohort of healthy SARS-CoV-2 naïve participants were enrolled in this study during a three-dose BNT162b2 vaccine series. Serum samples were collected from vaccinees over 420 days and screened for antigen (Ag)-specific antibody titers, IgG subclass distribution, and neutralizing antibody (nAb) responses. Vaccine boosting restored peak Ag-specific titers with sustained α-RBD IgG and IgA antibody responses when measured at six months post-boost. RBD- and spike-specific IgG4 antibody levels were markedly elevated in three-dose but not two-dose immune sera. Although strong neutralization responses were detected in two- and three-dose vaccine sera, these rapidly decayed to pre-immune levels by four and six months, respectively. While boosters enhanced serum IgG Ab reactivity and nAb responses against variant strains, all variants tested showed resistance to two- and three-dose immune sera. Our data reflect the poor durability of vaccine-induced nAb responses which are a strong predictor of protection from symptomatic SARS-CoV-2 infection. The induction of IgG4-switched humoral responses may permit extended viral persistence via the downregulation of Fc-mediated effector functions.

An Update in COVID-19 Vaccine Reactions in 2023: Progress and Understanding

It has been 3 years since the coronavirus disease 2019 (COVID-19) pandemic was initially declared, and 2 years have passed since the first COVID-19 vaccines were introduced. Since then, 13.2 billion COVID-19 vaccine doses have been administered worldwide, largely with multiple doses of messenger RNA vaccines. Although mild local and systemic adverse effects after COVID-19 vaccination are common, serious adverse effects following immunization are rare, particularly when compared with the large number of vaccine doses administered. Immediate and delayed reactions are relatively common and present similarly to allergic and hypersensitivity reactions. Despite this, reactions generally do not commonly recur, cause sequelae, or contraindicate revaccination. In this Clinical Management Review, we provide an updated perspective of COVID-19 vaccine reactions, their spectrum and epidemiology, and recommended approaches to evaluation and management.

Effectiveness of the second COVID-19 booster against Omicron: a large-scale cohort study in Chile

In light of the ongoing COVID-19 pandemic and the emergence of new SARS-CoV-2 variants, understanding the effectiveness of various booster vaccination regimens is pivotal. In Chile, using a prospective national cohort of 3.75 million individuals aged 20 or older, we evaluate the effectiveness against COVID-19-related intensive care unit (ICU) admissions and death of mRNA-based second vaccine boosters for four different three-dose background regimes: BNT162b2 primary series followed by a homologous booster, and CoronaVac primary series followed by an mRNA booster, a homologous booster, and a ChAdOx-1 booster. We estimate the vaccine effectiveness weekly from February 14 to August 15, 2022, by determining hazard ratios of immunization over non-vaccination, accounting for relevant confounders. The overall adjusted effectiveness of a second mRNA booster shot is 88.2% (95%CI, 86.2-89.9) against ICU admissions and 90.5% (95%CI 89.4-91.4) against death. Vaccine effectiveness shows a mild decrease for all regimens and outcomes, probably linked to the introduction of BA.4 and BA.5 Omicron sub-lineages and the waning of immunity. Based on our findings, individuals might not need additional boosters for at least 6 months after receiving a second mRNA booster shot in this setting.

Effectiveness of booster vaccination with inactivated COVID-19 vaccines against SARS-CoV-2 Omicron BA.2 infection in Guangdong, China: a cohort study

The effectiveness of COVID-19 vaccines wanes over time and the emergence of the SARS-CoV-2 Omicron variant led to the accelerated expansion of efforts for booster vaccination. However, the effect and contribution of booster vaccination with inactivated COVID-19 vaccines remain to be evaluated. We conducted a retrospective close contacts cohort study to analyze the epidemiological characteristics and Omicron infection risk, and to evaluate the effectiveness of booster vaccination with inactivated COVID-19 vaccines against SARS-CoV-2 infection, symptomatic COVID-19, and COVID-19 pneumonia during the outbreaks of Omicron BA.2 infection from 1 February to 31 July 2022 in Guangdong, China. A total of 46,547 close contacts were identified while 6.3% contracted Omicron BA.2 infection, 1.8% were asymptomatic infection, 4.1% developed mild COVID-19, and 0.3% had COVID-19 pneumonia. We found that females and individuals aged 0-17 or ≥ 60 years old were more prone to SARS-CoV-2 infection. The vaccinated individuals showed lower infection risk when compared with the unvaccinated people. The effectiveness of booster vaccination with inactivated COVID-19 vaccines against SARS-CoV-2 infection and symptomatic COVID-19 was 28.6% (95% CI: 11.6%, 35.0%) and 39.6% (95% CI: 30.0, 47.9) among adults aged ≥ 18 years old, respectively when compared with full vaccination. Booster vaccination provided a moderate level of protection against SARS-CoV-2 infection (VE: 49.9%, 95% CI: 22.3%-67.7%) and symptomatic COVID-19 (VE: 62.6%, 95% CI: 36.2%-78.0%) among adults aged ≥ 60 years old. Moreover, the effectiveness of booster vaccination was 52.2% (95% CI: 21.3%, 70.9%) and 83.8% (95% CI: 28.1%, 96.3%) against COVID-19 pneumonia in adults aged ≥ 18 and ≥ 60 years old, respectively. The reduction of absolute risk rate of COVID-19 pneumonia in the booster vaccination group was 0·96% (95% CI: 0.33%, 1.11%), and the number needed to vaccinate to prevent one case of COVID-19 pneumonia was 104 (95% CI: 91, 303) in adults aged ≥ 60 years old. In summary, booster vaccination with inactivated COVID-19 vaccines provides a low level of protection against infection and symptomatic in adults of 18-59 years old, and a moderate level of protection in older adults of more than 60 years old, but a high level of protection against COVID-19 pneumonia in older adults.

Safety of monovalent and bivalent BNT162b2 mRNA COVID-19 vaccine boosters in at-risk populations in Israel: a large-scale, retrospective, self-controlled case series study

BACKGROUND

COVID-19 continues to be a major health threat, particularly among at-risk groups, including individuals aged 60 years or older and people with particular medical conditions. Nevertheless, the absence of sufficient vaccine safety information is one of the key contributors to vaccine refusal. We aimed to assess the short-term safety profile of the BNT162b2 mRNA COVID-19 vaccine booster doses.

METHODS

In this self-controlled case series study, we used a database of members of the largest health-care organisation in Israel. We analysed the medical records of individuals at risk of COVID-19 complications who had received two doses of the monovalent BNT162b2 mRNA COVID-19 vaccine (tozinameran, Pfizer-BioNTech) as their primary course of vaccination and then also received BNT162b2 mRNA COVID-19 vaccine boosters between July 30, 2021, and Nov 28, 2022, as a monovalent first or second booster, or as a bivalent first, second, or third booster, or a combination of these. We included individuals who had active membership of the health-care organisation and who were alive (excluding COVID-19 deaths) throughout the entire study period. We excluded individuals who, during the study period, were either not active Clalit Health Services members or died of non-COVID-19 causes, and those who were infected with COVID-19 during the 7-day period after vaccination. Individuals' at-risk status was assessed on the day before the baseline period started. The primary outcome was non-COVID-19 hospitalisation for 29 adverse events that might be associated with vaccination. For each adverse event, we compared the risk difference of hospitalisation during a 28-day pre-vaccination baseline period versus during a 28-day post-vaccination period, using a non-parametric percentile bootstrap method.

FINDINGS

Of the 3 574 243 members of the health-care organisation, 1 073 110 received a first monovalent booster, 394 251 received a second monovalent booster, and 123 084 received a bivalent first, second, or third booster. Overall, we found no indication of an elevated risk of non-COVID-19 hospitalisation following administration of any of the booster vaccines (risk difference in events per 100 000 individuals: first monovalent booster -37·1 [95% CI -49·8 to -24·2]; second monovalent booster -37·8 [-62·2 to -13·2]; and bivalent booster -18·7 [-53·6 to 15·4]). Except for extremely rare elevated risks after the first monovalent booster-of myocarditis (risk difference 0·7 events per 100 000 individuals [95% CI 0·3-1·3]), seizures (2·2 [0·4-4·1]), and thrombocytopenia (2·6 [0·7-4·7])-we found no safety signals in other adverse events, including ischaemic stroke.

INTERPRETATION

This study provides the necessary vaccine safety assurances for at-risk populations to receive timed roll-out booster vaccinations. These assurances could reduce vaccine hesitancy and increase the number of at-risk individuals who opt to become vaccinated, and thereby prevent the severe outcomes associated with COVID-19.

FUNDING

Israel Science Foundation and Israel Precision Medicine Partnership programme.

Retinal Vein Occlusion Amongst People Vaccinated by mRNA- and Viral Vector- COVID-19 Vaccines: A Systematic Review

Vaccines are highly effective in lowering the mortality due to COVID-19. Although several suspected adverse events or side effects after vaccination including retinal vein occlusion (RVO) have been reported. We conducted a systematic review using PRISMA methods to analyze the occurrence of RVO among people vaccinated by COVID-19 mRNA- vs viral vector- vaccines on 4 databases from 1-1-2021 to 31-12-2022 using specified MeSH terms. All included studies were assessed using JBI critical appraisal tools for eligibility. The final included studies are 31 studies (n=78 cases from 75 patients; 3 of these patients suffered twice). The median age of the patients was 61 years (28 to 96 years old) and most of them were female (52.00%). Thirty-nine patients received the mRNA vaccine (52.00%), while 36 patients received the viral vector vaccine (48.00%) before the event. The RVO diagnoses are based on physical examination confirmed by Fluorescein Angiography (FA), and/or Optical Coherence Tomography (OCT). The median time interval between vaccination and RVO was 6 days in the mRNA vaccine group and 4 days in the viral vector vaccine group. Central retinal vein occlusion (CRVO) and Branch Retinal Vein Occlusion (BRVO) were tied as the most common diagnosis in the mRNA vaccine group (20.51% and 20.51%), whilst in the viral vector vaccine group CRVO was the most common diagnosis (17.94%). Most of these cases had good outcomes with improved visual impairment in one or both eyes. From this review, we could not ascertain that the RVO occurs due to the type of COVID-19 vaccines because of the detailed data on the dosage and the history of illness of each patient. However, the awareness that the RVO could develop after COVID-19 vaccination must be taken into consideration, even though it is rare.

Social network, political climate, income inequality, and Americans uptake of monovalent COVID-19 booster

The COVID-19 pandemic has posed an unprecedented impact on Americans for over three years. To control the damage, a booster shot becomes increasingly necessary because the efficacy of the initial vaccine is waning and new variants of the virus are emerging. This study aims to understand factors at both individual and state levels that influence one's decision to take the monovalent booster. We merged data from a national survey administered in the Spring of 2022 with state-level indicators of the political climate, income inequality, and public health conditions. Multilevel logistic regression is adopted for statistical estimation. Findings show contrasting effects of the social network. More vaccinated people in one's network promote booster uptake, while more family members and close friends who contracted the virus in one's network inhibit booster uptake. In addition, residents of states with more votes for the Democratic candidate in the 2020 general election are more likely to take the booster. Meanwhile, residents from states with high income inequality are less likely to become boosted. This study identified multilevel determinants of the individual decision to receive the monovalent COVID-19 booster. The results imply the need to leverage the social network, weaken partisanship salience, and reduce income inequality to encourage booster uptake.

The rates and symptoms of natural and breakthrough infection pre- and post- Covid-19 non-mRNA vaccination at various peaks amongst Iranian healthcare workers

BACKGROUND/AIMS

The aim of this study was to determine the rate of natural and breakthrough infection and related symptoms of Covid-19 amongst Iranian healthcare workers (HCWs) who were vaccinated by different non-mRNA-based vaccines at peak points.

METHODS

In this cross-sectional study, the RT-PCR test was performed for a total of 10,581 HCWs suspicious of Covid-19 infection. For each HCW, the frequency of SARS-CoV-2 infection and the time of transmission based on vaccination administration time and schedule were examined during different waves of the pandemic. Based on these findings, the study patients were divided into three groups: natural, natural/breakthrough, and breakthrough.

RESULTS

In total, 53% of the HCWs were exposed to SARS-CoV-2 infection between 1 and 5 times within two years after the current pandemic, while 20.7% and 32.3% experienced natural and breakthrough SARS-CoV-2 infection, respectively. Only 6% of the breakthrough-infected HCWs had naturally contracted SARS-CoV-2 infection during the initial waves. The highest natural peaks of infection occurred during the interval administration of the first and second dose of the first vaccination series, while the single highest peak of breakthrough infection belonged to the Omicron wave. It occurred simultaneously with the administration of the third vaccination dose. On the other hand, the highest rate of reinfection was observed amongst people who had received the Sinopharm and Bharat vaccines full-doses.

CONCLUSION

This study compared the clinical differences between the two peaks of Omicron and Delta. This study indicates the rates of natural and breakthrough SARS-CoV-2 infections according to vaccination schedules and different waves of the pandemic.

Racial and ethnic disparities in COVID-19 booster vaccination among U.S. older adults differ by geographic region and Medicare enrollment

Introduction

COVID-19 booster vaccines are highly effective at reducing severe illness and death from COVID-19. Research is needed to identify whether racial and ethnic disparities observed for the primary series of the COVID-19 vaccines persist for booster vaccinations and how those disparities may vary by other characteristics. We aimed to measure racial and ethnic differences in booster vaccine receipt among U.S. Medicare beneficiaries and characterize potential variation by demographic characteristics.

Methods

We conducted a cohort study using CVS Health and Walgreens pharmacy data linked to Medicare claims. We included community-dwelling Medicare beneficiaries aged ≥66 years who received two mRNA vaccine doses (BNT162b2 and mRNA-1273) as of 8/1/2021. We followed beneficiaries from 8/1/2021 until booster vaccine receipt, death, Medicare disenrollment, or end of follow-up (12/31/2021). Adjusted Poisson regression was used to estimate rate ratios (RRs) and 95% confidence intervals (CIs) comparing vaccine uptake between groups.

Results

We identified 11,339,103 eligible beneficiaries (mean age 76 years, 60% female, 78% White). Overall, 67% received a booster vaccine (White = 68.5%; Asian = 67.0%; Black = 57.0%; Hispanic = 53.3%). Compared to White individuals, Black (RR = 0.78 [95%CI = 0.78-0.78]) and Hispanic individuals (RR = 0.72 [95% = CI 0.72-0.72]) had lower rates of booster vaccination. Disparities varied by geographic region, urbanicity, and Medicare plan/Medicaid eligibility. The relative magnitude of disparities was lesser in areas where vaccine uptake was lower in White individuals.

Discussion

Racial and ethnic disparities in COVID-19 vaccination have persisted for booster vaccines. These findings highlight that interventions to improve vaccine uptake should be designed at the intersection of race and ethnicity and geographic location.

South African Thoracic Society position statement on the management of non-cystic fibrosis bronchiectasis in adults: 2023

Background

Bronchiectasis is a chronic lung disorder that affects the lives of many South Africans. Post-tuberculosis (TB) bronchiectasis is an important complication of previous pulmonary TB and a common cause of bronchiectasis in South Africa (SA). No previous statements on the management of bronchiectasis in SA have been published.

Objectives

To provide a position statement that will act as a template for the management of adult patients with bronchiectasis in SA.

Methods

The South African Thoracic Society appointed an editorial committee to compile a position statement on the management of adult non-cystic fibrosis (CF) bronchiectasis in SA.

Results

A position statement addressing the management of non-CF bronchiectasis in adults in SA was compiled. This position statement covers the epidemiology, aetiology, diagnosis, investigations and various aspects of management of adult patients with non-CF bronchiectasis in SA.

Conclusion

Bronchiectasis has largely been a neglected lung condition, but new research has improved the outlook for patients. Collaboration between interprofessional team members in patient management is important. In SA, more research into the epidemiology of bronchiectasis, especially post-TB bronchiectasis and HIV-associated bronchiectasis, is required.

Abstract

The South African Thoracic Society mandated a multidisciplinary team of healthcare providers to compile a position statement on the management of non-cystic fibrosis bronchiectasis in South Africa (SA). International guidelines on the management of bronchiectasis were reviewed and used as a basis from which the current position statement was compiled. This is the first position statement on the management of adult non-cystic fibrosis bronchiectasis in SA. A description of the epidemiology and aetiology of bronchiectasis is provided, as well as guidance on its diagnosis and management. The position statement provides guidance on the management of bronchiectasis to healthcare providers, policymakers and regulatory authorities.

Three-year COVID-19 and flu vaccinations among medical residents in a tertiary hospital in Italy: The threat of acceptance decline in seasonal campaigns

The COVID-19 vaccination campaign in Italy started in December 2020, and, due to the Omicron variant's emergence, a second booster dose was recommended for high-risk individuals and healthcare workers from July 2022. The aim of the study was to evaluate the vaccination coverages for the COVID-19 second booster dose and to identify predictors of its acceptance within the population of medical residents (MRs) of the Fondazione Policlinico Universitario "A. Gemelli" IRCCS (FPG) University Hospital. The study was conducted at FPG from October 4th to December 21st, 2022, and COVID-19 second booster dose and influenza vaccines were administered. The study analyzed collected data and conducted multivariate logistic regressions to explore potential predictors of vaccination adherence. The analyses performed were compared with the sample enrolled in FPG residency programs at the start of the COVID-19 vaccination campaign. 1968 MRs were involved in the 2022-2023 vaccination campaign (mean age 28.97, SD 3.44), and the second booster dose of COVID-19 vaccination coverage was low (18.80%). Almost all participants opted for co-administration of COVID-19 and influenza vaccinations, leading to a similar rate of influenza vaccination coverage (16.26%). Being a frontline resident, meaning a direct involvement in managing COVID-19 patients and vaccination campaigns, was the main predictor of vaccination adherence (OR 1.72, 95% CI 1.25-2.17). The dropping in influenza vaccination coverage in 2022-2023 and the low adherence to COVID-19 second booster dose among young physicians is concerning, calling for tailored vaccination campaigns and interventions.

Humoral response after a BNT162b2 heterologous third dose of COVID-19 vaccine following two doses of BBIBP-CorV among healthcare personnel in Peru

Background

The inactivated virus vaccine, BBIBP-CorV, was principally distributed across low- and middle-income countries as primary vaccination strategy to prevent poor COVID-19 outcomes. Limited information is available regarding its effect on heterologous boosting. We aim to evaluate the immunogenicity and reactogenicity of a third booster dose of BNT162b2 following a double BBIBP-CorV regime.

Methods

We conducted a cross-sectional study among healthcare providers from several healthcare facilities of the Seguro Social de Salud del Perú - ESSALUD. We included participants two-dose BBIBP-CorV vaccinated who presented a three-dose vaccination card at least 21 days passed since the vaccinees received their third dose and were willing to provide written informed consent. Antibodies were determined using LIAISON® SARS-CoV-2 TrimericS IgG (DiaSorin Inc., Stillwater, USA). Factors potentially associated with immunogenicity, and adverse events, were considered. We used a multivariable fractional polynomial modeling approach to estimate the association between anti-SARS-CoV-2 IgG antibodies' geometric mean (GM) ratios and related predictors.

Results

We included 595 subjects receiving a third dose with a median (IQR) age of 46 [37], [54], from which 40% reported previous SARS-CoV-2 infection. The overall geometric mean (IQR) of anti-SARS-CoV-2 IgG antibodies was 8,410 (5,115 - 13,000) BAU/mL. Prior SARS-CoV-2 history and full/part-time in-person working modality were significantly associated with greater GM. Conversely, time from boosting to IgG measure was associated with lower GM levels. We found 81% of reactogenicity in the study population; younger age and being a nurse were associated with a lower incidence of adverse events.

Conclusions

Among healthcare providers, a booster dose of BNT162b2 following a full BBIBP-CorV regime provided high humoral immune protection. Thus, SARS-CoV-2 previous exposure and working in person displayed as determinants that increase anti-SARS-CoV-2 IgG antibodies.

Humoral and Cellular Immune Responses of People Living With Human Immunodeficiency Virus After 3 Doses of Messenger RNA BNT162b2 Severe Acute Respiratory Syndrome Coronavirus 2 Vaccine: A Prospective Cohort Study

Background

Recent studies have shown good serological and cellular immune responses in people living with human immunodeficiency virus (PLWH) after receipt of 2 doses of messenger RNAA (mRNA) severe acute respiratory syndrome coronavirus 2 vaccine. Data are missing regarding the response after 3 vaccine doses.

Methods

We followed up a group of PLWH who received 3 doses of the mRNA BNT162b2 vaccine and for whom data of humoral immune response after 2 vaccine doses were available. Patients provided a blood sample 4-6 months after the booster dose. The aim of the study was to measure the serological and cellular response after the third dose and to evaluate factors associated with the vaccine response.

Results

Fifty patients have provided a serum sample for serological evaluation after the booster. The anti-receptor-binding domain (RBD) immunoglobulin (Ig) G titers were higher after the booster with a median delta of 3240 arbitrary units/mL. The median CD4+ T-cell count was 660/μL (interquartile range, 515-958/μL) and had no influence on the antibody level. Factors associated with lower delta included higher CD8+ T-cell count (P = .02) and longer time between the third dose and the blood test (P = .01). Higher anti-RBD IgG titer after the second vaccine (P = .03), as well as a longer interval between second and third doses (P = .031) were associated with higher delta. There was no increase in the median number of activated interferon γ+ and tumor necrosis factor α+ CD4+ T cells after the booster (n = 8).

Conclusions

The anti-RBD IgG level after 3 doses of mRNA BNT162b2 vaccine was higher than the level after 2 doses, suggesting additional value of the booster. Cellular response did not further increase after a booster.

Serologic Response and Safety after a Third Dose of the COVID-19 BNT162b2 Vaccine in Patients with Inflammatory Bowel Diseases

Vaccines are pivotal for control of the coronavirus disease (COVID-19) pandemic. Patients with inflammatory bowel diseases (IBDs) treated with antitumor necrosis factor (TNF)-α have lower serologic response after two COVID-19 vaccine doses. Data regarding a third vaccine dose are scarce. An Israeli multicenter prospective observational study recruited 319 subjects: 220 with IBD (79 treated with anti-TNFα) and 99 healthy control (HC) participants. All patients received two mRNA-BNT162b2 vaccines (Pfizer/BioNTech), 80% of whom received a third vaccine dose. Evaluation included disease activity, anti-spike (S) and nucleocapsid (N) antibody levels, anti-TNFα drug levels, and adverse events (AEs). All participants showed significant serologic response one month after receiving a third dose. However, three months later, the anti-S levels decreased significantly in patients treated with anti-TNFα compared with the non-anti-TNFα and HC groups. A correlation between serologic response to the third vaccine dose and anti-TNF drug levels was not found. No significant AE or IBD exacerbation was observed. Importantly, lower serologic response after the third vaccine dose predicted infection. A third dose of BNT162b2 is effective and safe in patients with IBD. Lower serologic response predicted infection, even in seropositive subjects. Lower serologic responses and their rapid decline suggest a fourth vaccine dose in this patient population.

TRACE-Omicron: Policy Counterfactuals to Inform Mitigation of COVID-19 Spread in the United States

The Omicron wave was the largest wave of COVID-19 pandemic to date, more than doubling any other in terms of cases and hospitalizations in the United States. In this paper, we present a large-scale agent-based model of policy interventions that could have been implemented to mitigate the Omicron wave. Our model takes into account the behaviors of individuals and their interactions with one another within a nationally representative population, as well as the efficacy of various interventions such as social distancing, mask wearing, testing, tracing, and vaccination. We use the model to simulate the impact of different policy scenarios and evaluate their potential effectiveness in controlling the spread of the virus. Our results suggest the Omicron wave could have been substantially curtailed via a combination of interventions comparable in effectiveness to extreme and unpopular singular measures such as widespread closure of schools and workplaces, and highlight the importance of early and decisive action.

COVID-19 transmission dynamics and the impact of vaccination: modelling, analysis and simulations

Despite the lifting of COVID-19 restrictions, the COVID-19 pandemic and its effects remain a global challenge including the sub-Saharan Africa (SSA) region. Knowledge of the COVID-19 dynamics and its potential trends amidst variations in COVID-19 vaccine coverage is therefore crucial for policy makers in the SSA region where vaccine uptake is generally lower than in high-income countries. Using a compartmental epidemiological model, this study aims to forecast the potential COVID-19 trends and determine how long a wave could be, taking into consideration the current vaccination rates. The model is calibrated using South African reported data for the first four waves of COVID-19, and the data for the fifth wave are used to test the validity of the model forecast. The model is qualitatively analysed by determining equilibria and their stability, calculating the basic reproduction number R 0 and investigating the local and global sensitivity analysis with respect to R 0 . The impact of vaccination and control interventions are investigated via a series of numerical simulations. Based on the fitted data and simulations, we observed that massive vaccination would only be beneficial (deaths averting) if a highly effective vaccine is used, particularly in combination with non-pharmaceutical interventions. Furthermore, our forecasts demonstrate that increased vaccination coverage in SSA increases population immunity leading to low daily infection numbers in potential future waves. Our findings could be helpful in guiding policy makers and governments in designing vaccination strategies and the implementation of other COVID-19 mitigation strategies.

Design and Analysis Heterogeneity in Observational Studies of COVID-19 Booster Effectiveness: A Review and Case Study

Background

Observational vaccine effectiveness (VE) studies based on real-world data are a crucial supplement to initial randomized clinical trials of Coronavirus Disease 2019 (COVID-19) vaccines. However, there exists substantial heterogeneity in study designs and statistical methods for estimating VE. The impact of such heterogeneity on VE estimates is not clear.

Methods

We conducted a two-step literature review of booster VE: a literature search for first or second monovalent boosters on January 1, 2023, and a rapid search for bivalent boosters on March 28, 2023. For each study identified, study design, methods, and VE estimates for infection, hospitalization, and/or death were extracted and summarized via forest plots. We then applied methods identified in the literature to a single dataset from Michigan Medicine (MM), providing a comparison of the impact of different statistical methodologies on the same dataset.

Results

We identified 53 studies estimating VE of the first booster, 16 for the second booster. Of these studies, 2 were case-control, 17 were test-negative, and 50 were cohort studies. Together, they included nearly 130 million people worldwide. VE for all outcomes was very high (around 90%) in earlier studies (i.e., in 2021), but became attenuated and more heterogeneous over time (around 40%-50% for infection, 60%-90% for hospitalization, and 50%-90% for death). VE compared to the previous dose was lower for the second booster (10-30% for infection, 30-60% against hospitalization, and 50-90% against death). We also identified 11 bivalent booster studies including over 20 million people. Early studies of the bivalent booster showed increased effectiveness compared to the monovalent booster (VE around 50-80% for hospitalization and death).Our primary analysis with MM data using a cohort design included 186,495 individuals overall (including 153,811 boosted and 32,684 with only a primary series vaccination), and a secondary test-negative design included 65,992 individuals tested for SARS-CoV-2. When different statistical designs and methods were applied to MM data, VE estimates for hospitalization and death were robust to analytic choices, with test-negative designs leading to narrower confidence intervals. Adjusting either for the propensity of getting boosted or directly adjusting for covariates reduced the heterogeneity across VE estimates for the infection outcome.

Conclusion

While the advantage of the second monovalent booster is not obvious from the literature review, the first monovalent booster and the bivalent booster appear to offer strong protection against severe COVID-19. Based on both the literature view and data analysis, VE analyses with a severe disease outcome (hospitalization, ICU admission, or death) appear to be more robust to design and analytic choices than an infection endpoint. Test-negative designs can extend to severe disease outcomes and may offer advantages in statistical efficiency when used properly.

Epidemiological study of vaccination against SARS-CoV-2 and its impact on COVID-19 progression in a cohort of patients in gran Canaria

Objectives. We analyzed the impact of age, sex, vaccination against COVID-19, immunosuppressive treatment, and comorbidities on patients' risk of requiring hospital admission or of death. Methods. Population-based observational retrospective study conducted on a cohort of 19,850 patients aged 12 years or more, who were diagnosed with COVID-19 between June 1st and December 31st, 2021, in the island of Gran Canaria. Results. Hypertension (18.5%), asthma (12.8%) and diabetes (7.2%) were the most frequent comorbidities; 147 patients died (0.7%). The combination of advanced age, male sex, cancer, coronary heart disease, immunosuppressive treatment, hospital admission, admission to the intensive care unit, mechanical ventilation and lack of complete COVID-19 vaccination or booster dose was strongly predictive of mortality (p < 0.05); 831 patients required hospital admission and it was more frequent in men, older age groups, and patients with cancer, diabetes, arterial hypertension, chronic obstructive pulmonary disease, congestive heart failure or immunosuppressive treatment. The COVID-19 vaccine booster dose was associated with a lower risk of death ([OR] 0.11, 95% CI 0.06-0.21, p < 0.05) or hospital admission ([OR] 0.36, 95% CI 0.29-0.46, p < 0.05). Conclusions. Cancer, coronary heart disease, and immunosuppressive treatment were associated with increased COVID-19 mortality. More complete vaccination was associated with lower risk of hospital admission or death. Three doses of the SARS-CoV-2 vaccine were highly associated with the prevention of death and hospital admission in all age groups. These findings suggest that COVID-19 vaccination can help bring the pandemic under control.

Longer-term effectiveness of a heterologous coronavirus disease 2019 (COVID-19) vaccine booster in healthcare workers in Brazil

Objective

To compare the long-term vaccine effectiveness between those receiving viral vector [Oxford-AstraZeneca (ChAdOx1)] or inactivated viral (CoronaVac) primary series (2 doses) and those who received an mRNA booster (Pfizer/BioNTech) (the third dose) among healthcare workers (HCWs).

Methods

We conducted a retrospective cohort study among HCWs (aged ≥18 years) in Brazil from January 2021 to July 2022. To assess the variation in the effectiveness of booster dose over time, we estimated the effectiveness rate by taking the log risk ratio as a function of time.

Results

Of 14,532 HCWs, coronavirus disease 2019 (COVID-19) was confirmed in 56.3% of HCWs receiving 2 doses of CoronaVac vaccine versus 23.2% of HCWs receiving 2 doses of CoronaVac vaccine with mRNA booster (P < .001), and 37.1% of HCWs receiving 2 doses of ChAdOx1 vaccine versus 22.7% among HCWs receiving 2 doses of ChAdOx1 vaccine with mRNA booster (P < .001). The highest vaccine effectiveness with mRNA booster was observed 30 days after vaccination: 91% for the CoronaVac vaccine group and 97% for the ChAdOx1 vaccine group. Vacine effectiveness declined to 55% and 67%, respectively, at 180 days. Of 430 samples screened for mutations, 49.5% were SARS-CoV-2 delta variants and 34.2% were SARS-CoV-2 omicron variants.

Conclusions

Heterologous COVID-19 vaccines were effective for up to 180 days in preventing COVID-19 in the SARS-CoV-2 delta and omicron variant eras, which suggests the need for a second booster.

Vaccine-Induced Immune Thrombotic Thrombocytopenia following BNT162b2 mRNA COVID-19 Booster: A Case Report

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a life-threatening complication caused by platelet activation via platelet factor 4 (PF4) antibodies. We report a healthy 28-year-old man who developed hemoptysis, bilateral leg pain, and headaches three weeks after his third dose of the COVID-19 vaccine with the first BNT162b2 (from Pfizer-BioNTech) injection. He had previously had the first and second doses with ChAdOx1 nCov-19 without any discomfort. Serial investigations demonstrated pulmonary embolisms, cerebral sinus, and deep iliac venous thrombosis. Positive PF4 antibody assay (ELISA) confirmed the diagnosis of VITT. He had a prompt response to intravenous immunoglobulins (IVIGs) at a total dose of 2 g/kg and his symptoms are now in remission with anticoagulant. Although the definite mechanism is unknown, the VITT was most likely triggered by his COVID-19 vaccine. We report this case of VITT following BNT162b2, a mRNA-based vaccine, and suggest that VITT could still happen without the adenoviral vector vaccines.