Immune responses to SARS-CoV-2 infection and COVID-19 vaccines

Coronavirus disease 2019 (COVID-19) is currently a major public health concern causing devastating sociological, economic, and psychological damage to livelihood all over the world. The most intense severity of COVID-19 is not only acute respiratory distress syndrome (ARDS), it also causes multi-organ failure, the post-infection secondary effect as well as death. The fast-mutating ability and high transmissibility rate of the virus cause emergence of the new variants and also the occurrence of breakthrough infections. Evidence suggests that vaccination against COVID-19 has been effective at preventing the severity of illness, hospitalization, and death. The efficacy of vaccines depends on multiple factors including the host’s ability to mount a robust and sustainable immune response, the virus’s ability to mutate its genome, and programmatic factors such as vaccine dose, storage, dosing schedules, etc. In this article, an overview of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, its pathogenesis, host immune responses to infection, and different type of COVID-19 vaccines, including vaccine efficacy and adverse effects are described.