COVID-19 Vaccines: Overview, Efficacy, Safety and Challenges

The rapid and extraordinary development and deployment of Coronavirus disease 2019 (COVID-19) vaccines worldwide represent an unprecedented achievement in the history of vaccine development. This chapter provides an overview of COVID-19 vaccine strategies, platforms, clinical trials, and regulatory frameworks. Vaccine safety, efficacy, herd immunity, and severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) variants are also discussed. Real world challenges confronted include the ethics of vaccine allocation, vaccine nationalism, vaccine hesitancy, and vaccine passports. © 2023 by World Scientific Publishing Co. Pte. Ltd.

Adverse reactions and safety profile of the mRNA COVID-19 vaccines among Asian military personnel

INTRODUCTION: The use of novel mRNA platforms for COVID-19 vaccines raised concern about vaccine safety, especially in Asian populations that made up less than 10% of study populations in the pivotal vaccine trials used for emergency use authorisation. Vaccine safety issues also remain a concern in assessing the clinical risks and benefits of vaccine boosters, particularly in specific age groups or segments of the population. This study describes a vaccination exercise involving Asian military personnel, and the adverse reactions and safety events observed. METHODS: Minor adverse reactions, hospitalisations and adverse events of special interest were monitored as part of the organisation's protocol for safety monitoring of COVID-19 vaccinations. All vaccine recipients were invited to complete an online adverse reaction questionnaire. Medical consults at the military's primary healthcare facilities were monitored for vaccine-related presentations. All hospitalisations involving vaccine recipients were analysed. Adverse reaction rates between doses, vaccines and age groups were compared. RESULTS: A total of 127,081 mRNA vaccine doses were administered to 64,661 individuals up to 24 July 2021. Common minor adverse reactions included fever/chills, body aches and injection site pain. These were more common after dose 2. Younger individuals experienced minor adverse reactions more frequently. Rare cases of anaphylaxis, Bell's palsy and myocarditis/pericarditis were observed. No deaths occurred. CONCLUSION: Minor adverse reactions were less common than reported in other studies, and rates of anaphylaxis, Bell's palsy and myocarditis/pericarditis were comparable. Our study supports the favourable safety profile of mRNA COVID-19 vaccines, which may help guide decisions about booster doses if required.