The following is a study of “A Phase 2 Clinical Trial to Evaluate the Safety, Reactogenicity, and Immunogenicity of Different Prime-Boost Vaccination Schedules of 2013 and 2017 A(H7N9) Inactivated Influenza Virus Vaccines Administered with and without AS03 Adjuvant in Healthy US Adults,” published in the March 2024 issue of Infectious Disease by Rostad et al.
Researchers conducted a prospective study evaluating the safety and immunogenicity of 2013 and 2017 A(H7N9) inactivated influenza vaccines (IIVs) and the impact of AS03 adjuvant, prime-boost interval, and priming effects, informing pandemic preparedness strategies.
They enrolled 180 healthy adults aged 19–50 in a Phase 2 clinical trial. Participants were randomly assigned to six vaccination groups, comparing homologous and heterologous prime-boost strategies with two boost intervals (21 vs. 120 days) and two dosages (3.75 or 15 μg) administered with or without AS03 adjuvant.
The results showed that two doses of A(H7N9) IIV were well tolerated without safety issues. Most participants experienced mild to moderate reactogenicity, which was more pronounced with adjuvant. Adjuvanted second doses and longer prime-boost intervals yielded higher immune responses. The highest hemagglutination inhibition geometric mean titer (GMT) against the 2017 A(H7N9) strain was observed in the homologous, adjuvanted 3.75 μg+AS03/2017 group (GMT: 133.4, 95% CI 83.6,212.6).
Investigators concluded that incorporating AS03 adjuvant and extending boost intervals enhances antibody responses, offering insights for pandemic preparedness.
Source: academic.oup.com/cid/advance-article-abstract/doi/10.1093/cid/ciae173/7636247
