MONDAY, Jan. 24, 2022 (HealthDay News) — For healthcare workers who received a priming dose of the Ad26.COV2.S vaccine, Ad26.COV2.S and mRNA boosters are immunogenic, with the most stronger after a booster with an mRNA-based vaccine, according to a study published online January 19 in the New England Journal of Medicine.
Roos SG Sablerolles, MD, of the Erasmus University Medical Center in Rotterdam, the Netherlands, and colleagues conducted a single-blind, multicenter, randomized controlled trial involving healthcare workers who received a priming dose of the vaccine Ad26.COV2.S. Immunogenicity and reactogenicity were assessed 28 days after receipt of no boost, Ad26.COV2.S boost, mRNA-1273 boost, or BNT162b2 boost.
The researchers found that compared to a single Ad26.COV2.S vaccination, a homologous or heterologous booster vaccination in 434 participants produced higher levels of S-specific binding antibodies, neutralizing antibodies and cell responses. T cells. Compared to homologous boosting, heterologous regimens that included mRNA-based vaccines resulted in a significantly greater increase in binding antibodies. The most immunogenic was the mRNA-1273 boost, which was associated with higher reactogenicity than the BNT162b2 and Ad26.COV2.S boosts. During the first two days following booster administration, local and systemic reactions were generally mild to moderate.
“One-shot Ad26.COV2.S vaccination adequately primes the immune system,” the authors write. “We found that in the face of waning immunity and circulating severe acute respiratory syndrome coronavirus 2 variants, these responses were stimulated more effectively with mRNA-based vaccines.”
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