COVID-19 Vaccine Evolution and Beyond

Modelling the Relative Vaccine Efficacy of ARCT-154, a Self-Amplifying mRNA COVID-19 Vaccine, versus BNT162b2 Using Immunogenicity Data

Background: Self-amplifying mRNA vaccines have the potential to increase the magnitude and duration of protection against COVID-19 by boosting neutralizing antibody titers and cellular responses. Methods: In this study, we used the immunogenicity data from a phase 3 randomized trial comparing the immunogenicity of ARCT-154, a self-amplifying mRNA COVID-19 vaccine, with BNT162b2 mRNA COVID-19 vaccine to estimate the relative vaccine efficacy (rVE) of the two vaccines over time in younger (<60 years) and older (≥60 years) adults. Results: By day 181 post-vaccination, the rVE against symptomatic and severe Wuhan-Hu-1 disease was 9.2-11.0% and 1.2-1.5%, respectively, across age groups whereas the rVE against symptomatic and severe Omicron BA.4/5 disease was 26.8-48.0% and 5.2-9.3%, respectively, across age groups. Sensitivity analysis showed that varying the threshold titer for 50% protection against severe disease up to 10% of convalescent sera revealed incremental benefits of ARCT-154 over BNT162b2, with an rVE of up to 28.0% against Omicron BA.4/5 in adults aged ≥60 year. Conclusions: Overall, the results of this study indicate that ARCT-154 elicits broader and more durable immunogenicity against SARS-CoV-2, translating to enhanced disease protection, particularly for older adults against Omicron BA.4/5.

Retinal Vascular Occlusions After COVID-19 Vaccination in South Korea: A Nation-Wide Population-Based Study

PURPOSE

To investigate the association between the retinal vascular occlusion and vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

METHODS

This nationwide population-based cohort study included 2,742,065 individuals aged ≥ 20 years who were vaccinated against SARS-CoV-2 from March 1, 2021, to December 31, 2021, and unvaccinated individuals matched at a ratio of approximately 1:10 by gender and age, all without a history of retinal vascular occlusion. The occurrence of retinal vascular occlusion was observed up to 60 days after the 1st vaccination date in the vaccination group, while 60 days from January 1, 2021, in the non-vaccination group. The risk of developing retinal vascular occlusion was compared between vaccinated and unvaccinated subjects. Risks were also compared among the different types of vaccines.

RESULTS

Vaccination lowered the risk of retinal vascular occlusion, with an odds ratio (OR) of 0.80 (95% confidence interval (CI), 0.64-0.99; p = 0.039). For individuals aged < 40 years, the vaccination lowered the risk of retinal vascular occlusion occurrence significantly compared with those over the age of 40 (OR, 0.35 for age 20-39, 0.83 for age 40-64, 0.81 for age ≥ 65; P for interaction = 0.028). There was a significant difference in the ORs for retinal vascular occlusion among the four vaccine types (p < 0.001).

CONCLUSIONS

SARS-CoV-2 vaccination did not increase the risk of retinal vascular occlusion. However, the risk levels differed depending on the type of vaccine used. Considering the ongoing evolution of SARS-CoV-2 vaccines, it is imperative to conduct additional assessments of the recently introduced vaccines.

Hesperidin, a Potential Antiviral Agent against SARS-CoV-2: The Influence of Citrus Consumption on COVID-19 Incidence and Severity in China

This review examines hesperidin, a citrus bioflavonoid, as a potential antiviral agent against SARS-CoV-2. The COVID-19 pandemic has demanded an urgent need to search for effective antiviral compounds, including those of natural origin, such as hesperidin. The review provides a comprehensive analysis of the chemical properties, bioavailability and antiviral mechanisms of hesperidin, particularly its potential efficacy against SARS-CoV-2. A review of databases, including PubMedPico, Scopus and Web of Science, was conducted using specific keywords and search criteria in accordance with PRISMA (Re-porting Items for Systematic Reviews and Meta-Analysis) guidelines between 2020 and 2024. Of the 207 articles, 37 were selected for the review. A key aspect is the correlation of in vitro, in silico and clinical studies on the antiviral effects of hesperidin with epidemiological data on citrus consumption in China during 2020-2024. The importance of integrating laboratory findings with actual consumption patterns to better understand the role of hesperidin in mitigating COVID-19 was highlighted, and an attempt was made to analyze epidemiological studies to examine the association between citrus juice consumption as a source of hesperidin and the incidence and severity of COVID-19 using China as an example. The review identifies consistencies and discrepancies between experimental and epidemiological data, highlighting the need to correlate the two fields to better understand the potential of hesperidin as an agent against SARS-CoV-2. Challenges and limitations in interpreting the results and future research perspectives in this area are discussed. The aim of this comprehensive review is to bridge the gap between experimental studies and epidemiological evidence and to contribute to the understanding of their correlation.

COVID-19 vaccination willingness among people living with HIV in Shijiazhuang, China: a cross-sectional survey

Objectives

The COVID-19 pandemic imposed an enormous disease and economic burden worldwide. SARS-CoV-2 vaccination is essential to containing the pandemic. People living with HIV (PLWH) may be more vulnerable to severe COVID-19 outcomes; thus, understanding their vaccination willingness and influencing factors is helpful in developing targeted vaccination strategies.

Methods

A cross-sectional study was conducted between 15 June and 30 August 2022 in Shijiazhuang, China. Variables included socio-demographic characteristics, health status characteristics, HIV-related characteristics, knowledge, and attitudes toward COVID-19 vaccination and COVID-19 vaccination status. Multivariable logistic regression was used to confirm factors associated with COVID-19 vaccination willingness among PLWH.

Results

A total of 1,428 PLWH were included, with a 90.48% willingness to receive the COVID-19 vaccination. PLWH were more unwilling to receive COVID-19 vaccination for those who were female or had a fair/poor health status, had an allergic history and comorbidities, were unconvinced and unsure about the effectiveness of vaccines, were unconvinced and unsure about the safety of vaccines, were convinced and unsure about whether COVID-19 vaccination would affect ART efficacy, or did not know at least a type of domestic COVID-19 vaccine. Approximately 93.00% of PLWH have received at least one dose of the COVID-19 vaccine among PLWH, and 213 PLWH (14.92%) reported at least one adverse reaction within 7 days.

Conclusion

In conclusion, our study reported a relatively high willingness to receive the COVID-19 vaccination among PLWH in Shijiazhuang. However, a small number of PLWH still held hesitancy; thus, more tailored policies or guidelines from the government should be performed to enhance the COVID-19 vaccination rate among PLWH.

Multiple antigen presenting system (MAPS): state of the art and potential applications

INTRODUCTION

Technological innovations have been instrumental in advancing vaccine design and protective benefit. Improvements in the safety, tolerability, and efficacy/effectiveness profiles have profoundly reduced vaccine-preventable global disease morbidity and mortality. Here we present an original vaccine platform, the Multiple Antigen Presenting System (MAPS), that relies on high-affinity interactions between a biotinylated polysaccharide (PS) and rhizavidin-fused pathogen-specific proteins. MAPS allows for flexible combinations of various PS and protein components.

AREAS COVERED

This narrative review summarizes the underlying principles of MAPS and describes its applications for vaccine design against bacterial and viral pathogens in non-clinical and clinical settings.

EXPERT OPINION

The utilization of high-affinity non-covalent biotin-rhizavidin interactions in MAPS allows for combining multiple PS and disease-specific protein antigens in a single vaccine. The modular design enables a simplified exchange of vaccine components. Published studies indicate that MAPS technology may support enhanced immunogenic breadth (covering more serotypes, inducing B- and T-cell responses) beyond that which may be elicited via PS- or protein-based conjugate vaccines. Importantly, a more detailed characterization of MAPS-based candidate vaccines is warranted, especially in clinical studies. It is anticipated that MAPS-based vaccines could be adapted and leveraged across numerous diseases of global public health importance.

Effectiveness of the Booster Dose in Protecting against COVID-19, Colombia 2022

Vaccination has proven to be one of the most effective strategies against the COVID-19 pandemic. Several studies have evaluated and confirmed its effectiveness in different populations, particularly in reducing severe outcomes such as hospitalization and death. Some studies have investigated the effectiveness of vaccination against the infection, identifying the need for booster doses. This study aimed to explore the effectiveness of the vaccination schedule on the probability of infection in a sample of Colombian patients during the fourth wave of the COVID-19 pandemic, which was associated with the emergence and predominance of the Omicron variant. A cross-sectional study was conducted on individuals who underwent RT-PCR testing for COVID-19 detection in a dedicated laboratory in Bogotá, Colombia, between 30 December 2021 and 7 February 2022. A total of 1468 subjects was included in the study, of whom 36.6% (n = 538) had a positive PCR test for COVID-19. The comparison between fully vaccinated individuals with a booster dose and those without the booster dose revealed a 28% reduction in the odds of infection (OR = 0.719 CI 0.531-0.971). Age (OR = 1.009 CI 1.001-1.018) and low economic status (OR = 1.812 CI 1.416-2.319) were associated with an increased risk of infection. These findings suggest the need for a booster vaccination in the general population to improve the prevention rates of SARS-CoV-2 infection and mitigate severe outcomes.