From the Guidelines
Get your flu shot for the 2024-2025 season as soon as it becomes available, typically in early fall, as it is expected to reduce the risk of illness by 40-60%. The vaccine is recommended for everyone 6 months and older, with rare exceptions, as stated in the recommendations for prevention and control of influenza in children, 2024-2025 1. It's especially important for high-risk groups like young children, older adults, pregnant women, and those with chronic health conditions.
Key Points to Consider
- Most people should get the standard quadrivalent flu shot, which protects against four flu virus strains.
- Adults 65 and older may benefit from high-dose or adjuvanted vaccines for enhanced immune response, as recommended by the Advisory Committee on Immunization Practices - United States, 2024-25 influenza season 1.
- It takes about two weeks after vaccination for antibodies to develop and provide protection.
- Getting vaccinated early allows your body to build immunity before flu season peaks, typically between December and February.
- The vaccine's effectiveness can vary based on how well it matches circulating virus strains and individual factors like age and overall health, as discussed in the prevention and control of seasonal influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices - United States, 2024-25 influenza season 1.
- Even when the match isn't perfect, vaccination can still reduce the severity of illness if you do get the flu.
- Remember, the flu shot cannot give you the flu, as it contains inactivated virus.
- Some people may experience mild side effects like soreness at the injection site or low-grade fever, which are normal immune responses.
From the Research
Effectiveness of Influenza Vaccine
The effectiveness of the influenza vaccine can vary from season to season, depending on several factors such as the age and immune competence of the vaccinee and the antigenic relatedness of vaccine strains to circulating strains 2.
Factors Influencing Vaccine Effectiveness
- Age: Vaccine effectiveness is generally higher in children and young healthy adults, with estimates ranging from 70-90% in randomized, placebo-controlled trials when the vaccine strains are well matched to circulating strains 2.
- Immune competence: Individuals with compromised immune systems may have lower vaccine effectiveness.
- Antigenic relatedness: The effectiveness of the vaccine is reduced when there is a suboptimal match between the vaccine strains and the circulating strains.
Interim Estimates for 2023-2024 Season
Interim estimates of vaccine effectiveness for the 2023-2024 season in the United States showed that the vaccine was effective in reducing the risk of medically attended influenza virus infection, with estimates ranging from 33% to 67% against influenza-associated outpatient visits and 41% to 61% against hospitalization 3.
Recommendations for 2024-2025 Season
While there is no direct evidence available for the 2024-2025 season, the recommendations for the 2023-2024 season can provide some insight. The National Advisory Committee on Immunization (NACI) and other health organizations recommend that an age-appropriate influenza vaccine should be offered annually to all individuals aged six months and older who do not have a contraindication to the vaccine, with particular focus on high-risk groups such as healthcare workers, adults aged 60 years and older, and individuals with comorbidities 4, 5.
High-Risk Groups
- Healthcare workers
- Adults aged 60 years and older
- Individuals with comorbidities
- Pregnant women
- Children 6-59 months of age
- Family members and caregivers of infants under 6 months of age
- People who work in nursery institutions, primary and secondary schools, and supervision places 4