The effects of vaccine booster doses on the adaptive evolution of the virus.
By Dr. Priyom Bose, Ph.D.Oct 25 2023Reviewed by Lily Ramsey, LLM Viruses naturally adapt to positive and negative environmental pressures, such as natural or vaccine-induced active immunity or passive immunity mediated by the transfer of antibodies from another individual.
This phenomenon has been held responsible for the rapid spread and high rate of breakthrough infections with Omicron. Such convergent mutations occur against an increasing but incomplete antibody response that cannot neutralize a rapidly evolving virus. This drives the appearance of common or recurrent mutations in different strains.
In this case, Omicron rapidly became dominant and has continued to spread and change until the present day. Related StoriesThis was conducted for each variant of the virus, categorizing each shift by the vaccine status of the individual, the ancestral descent of the viral strain, and the demographic and clinical characteristics of the participants.
Interestingly, the first booster doses were rolled out on a large scale during the Delta wave, but almost all subsequent breakthrough infections and reinfections were caused by the Omicron variant. These, however, poorly adapted the virus to spread or survive neutralizing antibodies – diffuse adaptive evolution.
High negative selection scores were observed with Omicron BA.2-BA.5, but not Delta or BA.1, indicating the rejection of multiple mutations so that the wildtype sequence was restored at those sites.
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