Why Are Flu Shots Different for Seniors?
As the body ages, the immune system's response to vaccines can weaken, leaving older adults more vulnerable to severe complications from influenza. For the 2025–2026 flu season, the CDC continues to emphasize the use of enhanced vaccines for individuals 65 years and older, moving away from a 'standard-dose for all' approach in this high-risk group. These specialized vaccines are designed to boost the immune response, providing better protection against the flu and potentially reducing the risk of severe outcomes like hospitalization and death.
The Preferential Recommendation: Enhanced Vaccines
For the 2025–2026 season, the CDC, through its Advisory Committee on Immunization Practices (ACIP), preferentially recommends one of three enhanced vaccine types for adults 65 and older. This preference is based on studies showing that these options can provide superior protection compared to standard-dose vaccines in this age group. The three recommended options are:
- High-Dose Vaccine (Fluzone High-Dose Quadrivalent): Contains four times the amount of antigen (the part of the vaccine that stimulates the immune system) as a standard flu shot. This higher concentration aims to create a stronger immune response.
- Adjuvanted Vaccine (Fluad Quadrivalent): Includes an ingredient called an adjuvant (MF59) to help create a stronger and more long-lasting immune response. It contains a standard dose of antigen but with the added boost.
- Recombinant Vaccine (Flublok Quadrivalent): Produced using a different manufacturing process that does not involve flu virus or eggs. It also contains three times the amount of antigen as a standard shot, leading to a stronger immune response.
What if an Enhanced Vaccine Isn't Available?
In situations where one of the three preferentially recommended vaccines is not available at the time of vaccination, the CDC states that any other age-appropriate inactivated influenza vaccine should be used. The key message is that getting vaccinated with any available flu shot is better than not getting vaccinated at all. Older adults should discuss the available options with their healthcare provider or pharmacist, but if a preferred vaccine isn't stocked, they should not delay getting another age-appropriate option.
Important Considerations for Seniors
Timing is Everything
Timing is especially important for older adults. The CDC recommends that vaccination should ideally occur during September or October. Early vaccination in July or August is generally not recommended for seniors because the immune protection can wane over the course of the flu season, which can extend well into the spring. However, if an opportunity for vaccination presents itself earlier and there is concern that a later vaccination might not be possible, it is still advisable to get the shot.
Additional Vaccinations
In addition to the annual flu shot, seniors should also ensure they are up-to-date on other important vaccinations. For instance, the CDC recommends pneumococcal vaccination for adults 50 years and older to protect against serious pneumococcal infections like pneumonia, a common flu complication. The pneumococcal vaccine can be administered at the same time as the flu shot. Furthermore, the flu and updated COVID-19 vaccines can be given during the same visit.
Comparison of Flu Vaccines for Adults 65+
| Feature | High-Dose (e.g., Fluzone HD) | Adjuvanted (e.g., Fluad) | Standard Dose (IIV4) | |||||
|---|---|---|---|---|---|---|---|---|
| Antigen Content | Four times a standard dose | Standard dose | Standard dose | |||||
| Immune Response | Designed to create a stronger response by boosting antigen content | Designed to create a stronger response by using an adjuvant | Weaker response in older adults | n | Preferred by CDC? | Yes | Yes | No, but acceptable if preferred unavailable |
| Use in 65+ | Preferentially recommended | Preferentially recommended | Recommended if preferred options are not available | |||||
| Side Effects | Potentially more side effects, such as soreness, fever, headache | May cause more local side effects at injection site than standard dose | Generally well-tolerated |
Safety and What to Expect
Flu shots are safe and effective, and the risk of experiencing serious side effects is very low. Side effects are usually mild and may include soreness, redness, or swelling at the injection site. Some people might also experience a low-grade fever, headache, or muscle aches for a day or two. These are not signs of the flu itself, but rather an indication that the immune system is building a protective response. The health benefits of getting a flu vaccine far outweigh the potential side effects.
The Bottom Line for Seniors
Getting an annual flu shot is a vital part of a senior's health regimen. Given the increased risk of severe illness, the CDC's guidance is clear: seek out one of the preferentially recommended enhanced vaccines, such as high-dose, adjuvanted, or recombinant options, in September or October. In conjunction with regular hand washing and avoiding close contact with sick people, this provides the best protection for a healthy flu season. Always have a discussion with your healthcare provider to determine the best vaccine and timing for your specific health needs.
An official summary of the CDC's annual recommendations can be found on their website. For detailed information on the 2025-2026 season's vaccine composition and guidelines, you can visit the CDC's official ACIP recommendations.
