Despite low efficacy, the CDC says the flu shot is a “critical tool” to prevent moderate-to-severe influenza in children and adolescents.

During the 2022–2023 flu season, the influenza vaccine was less than 50 percent effective at preventing emergency department/urgent care visits and hospitalizations among children and adolescents, according to a study funded by the Centers for Disease Control and Prevention (CDC).

The analysis, published Nov. 16, 2023, in Clinical Infectious Diseases, found the seasonal influenza vaccine was only 48 percent effective overall at reducing the risk of influenza-A-associated emergency department (ED) or urgent care (UC) visits, and only 40 percent effective at preventing hospitalizations.

Researchers analyzed acute respiratory illness-associated ED and UC visits or hospitalizations at 55 hospitals and 107 ED or UC sites within the VISION vaccine effectiveness network—a multistate collaboration with the CDC. Children and adolescents 6 months to 17 years were tested for influenza between October 2022 and March 2023.