Protective effectiveness and challenges of COVID-19 vaccines

ABSTRACT

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been a global pandemic. Safe and effective vaccination is critical to ending the epidemic of COVID-19. Although randomized clinical trials are considered the "gold standard" for evaluating intervention effects of vaccines, they have notable limitations. As mass vaccination campaigns against COVID-19 commence worldwide, vaccine effectiveness needs to be assessed for a range of outcomes across diverse populations in a noncontrolled setting. Meanwhile, SARS-CoV-2 variants continue to emerge during the global pandemic and may facilitate escape from current vaccine immune protection. Hence, COVID19 vaccines faced many challenges, such as safety, immunogenicity, and efficacy of the COVID-19 Vaccine in special populations, the duration of protective effectiveness, viral mutations and breakthrough infection, antibody-dependent enhancement effect, and pathogenic autoimmune and so on. This article summarizes th.