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SARS-CoV-2 variant replacement constrains vaccine-specific viral diversification.
Bethany L Dearlove1,2, Anthony C Fries3, Nusrat J Epsi2,4
1US Military HIV Research Program, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, United States.
Virus Evolution
|October 10, 2024
Summary
COVID-19 vaccine breakthrough infections did not significantly increase SARS-CoV-2 viral diversity. Rapid variant replacement, not vaccination, primarily influenced viral evolution, suggesting vaccine effects were overshadowed by widespread infections and vaccinations.
Area of Science:
- Virology
- Immunology
- Genomics
Background:
- COVID-19 vaccine breakthrough infections are a concern across SARS-CoV-2 variants.
- The role of vaccine-induced immune pressure on SARS-CoV-2 viral diversification is not fully understood.
Purpose of the Study:
- To investigate the impact of vaccination status on SARS-CoV-2 viral diversity.
- To assess the contribution of vaccine-specific viral diversification to vaccine failure.
Main Methods:
- Analysis of 595 SARS-CoV-2 sequences from Military Health System beneficiaries (Dec 2020 - Apr 2022).
- Comparison of viral sequences based on participant vaccination status.
- Investigation of viral diversity in the SARS-CoV-2 spike protein.
Main Results:
- Limited evidence suggests vaccination is associated with increased SARS-CoV-2 spike protein diversity.
- Little to no substantial sieve effect observed within major SARS-CoV-2 variants.
- Rapid variant replacement constrained vaccine strain immune escape.
Conclusions:
- Vaccine-mediated effects on viral diversity were likely subsumed by large-scale infections and vaccinations during rapid variant replacement periods.
- Sieve analysis methods may have limitations outside placebo-controlled trials for assessing vaccine effects.
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