Immunogenicity and reactogenicity of fractional vs. full booster doses of COVID-19 vaccines: a non-inferiority, randomised, double-blind, phase IV clinical trial in Brazil.

ABSTRACT:

Background

Fractional doses of vaccine to protect against COVID-19 offer the potential to expand vaccine availability, reduce side effects, and enhance vaccination campaign efficiency. This study aimed to assess the immune response and safety of fractional doses of SARS-CoV-2 booster vaccines compared to full doses in immunocompetent adults aged 18-60 who had previously received a full series of Sinovac, AZD1222 (AstraZeneca), or BNT162b2 (Pfizer/BioNTech).

Methods

This trial was structured as a parallel-group, double-blind, randomised Phase IV non-inferiority study, carried out in Campo Grande, Midwest, Brazil. After obtaining consent, eligible participants were randomised to one of 5-6 study arms, depending on their priming vaccine. Participants were followed for 21-60 day

SUBMITTER: Moreira Puga MA 

PROVIDER: S-EPMC11904515 | biostudies-literature | 2025 Apr

REPOSITORIES: biostudies-literature