COVID-19 mRNA booster provides additional protection, most beneficial for older adults
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Key takeaways:
- Boosting with a third dose of mRNA-1273 provided additional protection against COVID-19 during the delta and omicron waves.
- The booster dose provided was most beneficial for adults aged 65 and older.
BOSTON — Boosting with mRNA-1273 provided additional COVID-19 protection during the delta and omicron waves, and especially among older adults, according to data from the phase 3 coronavirus efficacy (COVE) trial presented at IDWeek.
“There is a need for a better understanding of the effect of age and the timing between booster doses on the vaccine’s efficacy and durability to help inform vaccination recommendations,” Dean Follmann, PhD, chief of the biostatistics research branch at the National Institute of Allergy and Infectious Diseases, told Healio.
“This research was a long-planned study to look at the effect of a third or booster dose of mRNA-1273 in SARS-CoV-2-naive individuals who had received the primary series of mRNA-1273 during the delta and omicron waves,” he said.
Through the COVE trial, Follmann and colleagues evaluated the effectiveness of the mRNA-1273 booster or third dose in approximately 17,000 boosted participants who previously received two doses of mRNA-1273 between July and October 2020 or December 2020 and April 2021, and a single mRNA-1273 booster beginning in September 2021.
Overall, the study showed that boosting provided additional protection against COVID-19 during the duration of the delta wave with an initial 83% reduction in COVID-19, which was maintained through 2 months of follow-up. Similar protection was seen against omicron, with the booster generating an initial 56% reduction in omicron COVID-19, which waned by 4 months post-vaccination.
The researchers also found that the benefit of boosting was greater among people aged 65 years and older, with the initial efficacy during omicron being 86% compared with 50% for those aged younger than 65.
“Because adults over the age of 65 are at higher risk of COVID-19, these data support the critical role vaccination plays in helping keep this age group protected,” he said.
Follmann added that the data suggest there was also a benefit of a longer dosing interval between a primary COVID-19 vaccination and booster dose, although the clinical impact of a longer interval is “complex.”
“A longer interval may have led to a 24% reduction in omicron COVID-19, but this is countered by an increased risk of COVID-19 while remaining unboosted,” he said. “While updated research is needed on the impact of age and timing on the efficacy of variant-targeting vaccines, these data could be used to inform modeling of vaccination policies.”
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Follmann D, et al. Abstract 1939. Presented at: IDWeek; Oct. 11-15, 2023; Boston.
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