Study Suggests Flu Vaccination Could Prevent Millions of Medical Visits

As reported by the U.S. Centers for Disease Control and Prevention (CDC), a new study published in The Journal of Infectious Diseases estimates that influenza (flu) vaccination reduced the risk of flu-related emergency department and urgent care (ED/UC) visits by almost half and hospitalizations by more than a one-third among U.S. adults during the 2022–2023 flu season.

According to the CDC, even in seasons with moderate vaccine effectiveness similar to the 2022–2023 season, flu vaccination is likely to prevent millions of flu-related medical visits, tens of thousands of hospitalizations, and thousands of deaths.

The last flu season saw unusually early and intense flu activity, with high hospitalization rates and co-circulation of other respiratory viruses, including SARS-CoV-2 and respiratory syncytial virus (RSV). Most influenza virus infections were caused by influenza A(H3N2) viruses well-matched to the vaccine.

In the Journal’s analysis, which looked at more than 100,000 acute respiratory illness-related healthcare encounters between October 2022 and March 2023, flu vaccination reduced the risk of influenza A-associated hospitalizations by 35% and ED/UC visits by 44%, with vaccine effectiveness varying by age group and care setting as follows:

Hospitalization

• Vaccinated people 18–64 years old were 23% less likely to be hospitalized with flu.
• Vaccinated people 65 years and older were 41% less likely to be hospitalized with flu.
• Similar vaccine effectiveness (VE) was also observed among hospitalized groups of people who are at higher risk for severe complications from flu, including older adults, those with immunocompromising conditions, and those with multiple underlying chronic medical conditions.

Emergency Department or Urgent Care

• VE against ED/UC encounters was similar among people 18–64 years old (45%) and 65 years and older (41%)
• VE against ED/UC encounters was also similar among those without and with immunocompromising conditions (44% and 38%, respectively).
• Most influenza virus infections were caused by influenza A(H3N2) viruses well-matched to the vaccine.

The CDC recommends that everyone six months and older get a seasonal flu vaccine each year. With flu activity increasing in most parts of the country, the CDC states that now is still a good time to get vaccinated.

For more information on dealing with the flu this season, check out Weathering the Cold and Flu Season.