Interim data show vaccine effectiveness of 51.9 percent in five South American countries during their flu season
By Elana Gotkine HealthDay Reporter
MONDAY, Sept. 11, 2023 (HealthDay News) — Influenza vaccination reduced the risk for influenza-associated hospitalizations by 52 percent in the March to September Southern Hemisphere 2023 influenza season, according to research published in the Sept. 8 issue of the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.
Ashley L. Fowlkes, Sc.D., from the CDC in Atlanta, and colleagues conducted an interim study to estimate vaccine effectiveness (VE) for preventing severe acute respiratory infection (SARI)-associated hospitalization using data from the Network for the Evaluation of Vaccine Effectiveness in Latin America and the Caribbean-influenza (la Red para la EvaluaciÃ³n de Vacunas en Latino AmÃ©rica y el Caribe-influenza [REVELAC-i]).
The researchers found that the adjusted VE against SARI hospitalization associated with any influenza virus during the 2023 Southern Hemisphere season was 51.9 percent, including 55.2 percent against the predominating A(H1N1)pdm09, based on data contributed by Argentina, Brazil, Chile, Paraguay, and Uruguay on 2,780 SARI patients hospitalized during March 27 to July 9, 2023.
“Preliminary REVELAC-i data from five Southern Hemisphere countries suggest that influenza vaccines were effective in preventing more than one half of influenza-associated hospitalizations among young children, persons with preexisting conditions, and older adults,” the authors write. “Evaluating influenza VE through integrated regional networks such as REVELAC-i provides valuable information that can guide public health practice.”
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