Vaccination against the H3N2 strain remains effective in reducing morbidity and mortality, even though its protection is lower in older adults compared to younger children.

While the vaccine is less effective against the H3N2 virus in older adults, it still significantly lowers the risk of severe influenza and related complications.

The findings indicate that vaccination significantly reduces the risk of severe influenza, ICU admissions, and mortality, particularly in high-risk groups such as individuals with cardiovascular or neurodegenerative diseases.

Vaccines against influenza A (H1N1) and B (IBV) have been shown to effectively reduce infection rates and complications in children under 5, adults aged 5-65, and seniors over 65.

Estanislao Nistal Villan, PhD, the principal investigator of the study, noted that the higher mutation and glycosylation rates of H3N2 may contribute to reduced vaccine effectiveness.

The effectiveness of vaccination should be evaluated based on its ability to prevent severe illness and death, rather than solely focusing on infection rates.

This large-scale study was conducted in collaboration with several institutions, including the National Center for Microbiology, 12 de Octubre University Hospital, and the National Influenza Center of Valladolid.

A comprehensive meta-analysis, involving data from over 38 countries and 6.5 million patients, highlights the critical role of influenza vaccination in public health.

The study suggests that vaccination can reduce the risk of death from severe influenza by three to four times, emphasizing its importance across all age groups.