The emergence of new variants and sub-variants of SARS-CoV-2 and the effectiveness of vaccines

ABSTRACT

At the end of 2020, variants of the SARS-CoV-2 virus appeared as a great risk to public's health and therefore, in order to prioritize global monitoring and research, they were placed in the category of variants of interest (VOIs), variants of concern (VOCs) and under monitoring variants (VUMs). As of April 2022, omicron (B.1.1.529) sub-variants of SARS-CoV-2, including BA.2.12.1, BA.4, and BA.5, are considered variants of concern with increased virulence and transmissibility. The omicron variant of SARS-CoV-2 is emerging in communities where people have already been infected with earlier variants and are now vaccinated, or people who have received two or three doses of the coronavirus vaccination. More than 130 countries worldwide have implemented booster programs to combat omicron. Despite preliminary findings that suggest booster doses may improve omicron protection, more research is needed to prove this. In the case of the COVID-19, it was recommended that at least 2 injections of the vaccine be given, and after 6 months we saw a decline in immunity. Taken together, the studies suggest that the BQ and XBB subtypes pose serious threats to current vaccines, inactivate all neutralizing antibodies, and may have spread in the population due to their evolution in evading antibodies. Though people still need to take this issue seriously and protect themselves. © 2023, Iranian Institute for Health Sciences Research. All rights reserved.