COVID-19 Vaccines and the Efficacy of Currently Available Vaccines Against COVID-19 Variants

Abstract

Severe acute respiratory syndrome coronavirus 2 is the seventh member of the Coronaviridiae family of viruses, which are thought to be transmitted by Chinese horseshoe bats. The virus undergoes mutations leading to variants such as B.1.1.7 (alpha), B.1.351 (beta), P.1 (gamma), and B.1.617 (delta), as well as the recent variant B.1.1.529 (omicron), which has around 30 deletions, making it a severely mutated form that lowers vaccination-induced protection. Vaccine efficacy is usually expressed as relative risk reduction, which is based on the ratio of attack rates with and without a vaccine, whereas absolute risk reduction is based on the entire population. Rather than two doses, recent research suggests that a third dose/booster dose may aid in protection against future variants. The constant influx of mutant variations is putting a strain on vaccine production. Despite the challenges, we are optimistic that the epidemic will be eradicated by achieving mass immunity and by ensuring that everyone receives vaccines at a faster rate.

Keywords: booster dose; corona; covaxin; efficacy; moderna; omicron; vaccine.

Figure 1. The earliest documented samples of COVID-19 variants according to the World Health Organization.

Yellow depicts the alpha variant, blue depicts the beta variant, green depicts the gamma variant, and red indicates the delta variant and their emergence in the respective countries. COVID-19: coronavirus disease 2019