One year safety and immunogenicity of AZD1222 (ChAdOx1 nCoV-19): Final analysis of a randomized, placebo-controlled phase 1/2 trial in Japan.
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Ishikawa K, Nascimento M, Asano M, Hirata H, Itoh Y, Kelly EJ, Matsui A, Olsson U, Shoemaker K, Green J
Vaccine 41 (29) 4199-4205 [2023-06-29; online 2023-06-02]
Long duration trial data for two-dose COVID-19 vaccines primary series' are uncommon due to unblinding and additional doses. We report one-year follow-up results from a phase 1/2 trial of AZD1222 (ChAdOx1 nCoV-19) in Japan. Adults (n = 256) seronegative for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) were stratified by age, 18-55 (n = 128), 56-69 (n = 86) and ≥70-year-old (n = 42), and randomized 3:1 to AZD1222 or placebo. Safety, immunogenicity, and exploratory efficacy data were collected until study Day 365. Safety was consistent with previous reports. In AZD1222 vaccinees, humoral responses against SARS-CoV-2 steadily declined over time. By Day 365, anti-SARS-CoV-2 spike-binding (spike) and receptor-binding domain (RBD) mean antibody titers remained above Day 15 levels and pseudovirus neutralizing antibodies were undetectable in many participants. AZD1222 is immunogenic and well tolerated in Japanese adults. Expected waning in anti-SARS-CoV-2 humoral responses was observed; spike and RBD antibody titers remained elevated. (ClinicalTrials.gov: NCT04568031).
PubMed 37271703
DOI 10.1016/j.vaccine.2023.05.015
Crossref 10.1016/j.vaccine.2023.05.015
pmc: PMC10237326
pii: S0264-410X(23)00542-X
ClinicalTrials.gov: NCT04568031