Study targets COVID-19 variant antibody effectiveness after Moderna vaccination

Researchers found that the effectiveness of the vaccine held for about 6 months in most adults, but began to be less effective at that time point.

The effectiveness of the mRNA-1273 vaccine (Moderna) vaccine may diminish over time with the subsequent appearance of the COVID-19 variants, according to first author Amarendra Pegu from the Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.

According to investigators, the effectiveness of the vaccine held for about 6 months in most adults, but began to be less effective at that time point.

Pegu and colleagues conducted the study1 in which they assessed how the Moderna vaccine held up against the variants: B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), B.1.429 (Epsilon), B.1.526 (Iota), and B.1.617.2 (Delta) in terms of the effect on the binding, neutralizing, and angiotensin-converting enzyme 2-competing antibodies that the Moderna vaccine elicited over 7 months.

They reported that cross-reactive neutralizing responses were rare after 1 dose and peaked about 2 weeks after the second dose at which point all patients had vaccine responses to all of the variants.

After this, the activity of the vaccine against the variants began to slide moderately to the 6-month point.

“Binding and functional antibodies against variants persisted in most subjects, albeit at low levels, for 6-months after the primary series of the mRNA-1273 vaccine,” the investigators concluded. “Across all assays, B.1.351 had the lowest antibody recognition. These data complement ongoing studies to inform the potential need for additional boost vaccinations.”

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Reference

1. Pegu A, O’Connell S, Schmidt S, et al. Durability of mRNA-1273 vaccine-induced antibodies against SARS-VoV-2 variants. Science published online August 12, 2021; DOI: 10.1126/science.abj4176