How effective is the flu vaccine?

Q: How effective was the flu vaccine during the 2022-23 season?

A: The effectiveness of the flu vaccine can vary, but it was quite significant during the 2022-23 season. Studies like the one by McLean et al. (2023) show that the vaccine was 54% effective against the influenza A virus, providing substantial protection, especially for individuals under 65 years old and children and adolescents experiencing symptomatic influenza.

Q: Does the effectiveness of the flu vaccine vary in different regions?

A: Yes, effectiveness can vary by region. For instance, during the same season in Europe, the effectiveness against influenza A ranged from 27% to 44%, according to Kissling et al. (2023). The variation often depends on factors like the match between the vaccine strains and the circulating strains and the age groups being considered.

Q: Why was the vaccine particularly effective for children last season?

A: The studies indicate that children benefited more from the vaccine, with higher effectiveness rates. This suggests that children’s immune responses to the vaccine can be more robust, or perhaps the strains impacting children were better matched to the vaccine strains that season.

Q: What was the overall impact of the flu vaccine in Canada during the same season?

A: In Canada, the effectiveness was similar to that of the U.S. Skowronski et al. (2023) reported an effectiveness of 54% against influenza A. This level of effectiveness was crucial in reducing the strain on healthcare resources during a season marked by early and unusual influenza activity.

Q: Why should people get vaccinated against the flu every year?

A: Despite the variations in effectiveness each year, the flu vaccine remains the best preventive measure against influenza. It significantly lowers the incidence of the disease and reduces severe outcomes. Annual vaccination is particularly important for protecting vulnerable populations and maintaining public health during the flu season. The ongoing research and updates to the vaccine formulations aim to improve their efficacy, making them an essential part of public health strategies each year.