Optimal Timing for Older Adults
For older adults, the timing of their annual flu shot is a strategic consideration to ensure protection lasts through the entire flu season. The Centers for Disease Control and Prevention (CDC) and other medical experts recommend that older adults, especially those aged 65 and over, get vaccinated in September or October.
- Why mid-fall is best: Immunity from the flu shot typically lasts about four to six months. Because older adults' immune responses can wane faster, getting vaccinated too early, such as in July or August, could leave them with diminished protection by February or March, when flu activity often peaks. A mid-fall vaccination ensures peak immunity during the winter months, when the risk of exposure is highest.
- Never too late: While September and October are ideal, getting a flu shot anytime during the flu season is beneficial. If you miss the optimal window, vaccination should still continue as long as flu viruses are circulating, even into January or later. Getting vaccinated later can still reduce the severity of illness and risk of complications.
Recommended Flu Vaccine Options
Older adults should seek specific types of flu vaccines that are designed to provide a more robust immune response. The CDC preferentially recommends three types of influenza vaccines for individuals aged 65 and older.
- High-Dose Inactivated Flu Vaccine: This vaccine contains four times the amount of antigen (the part of the vaccine that stimulates the immune response) compared to a standard flu shot. The brand name is Fluzone High-Dose Quadrivalent.
- Adjuvanted Flu Vaccine: This vaccine includes an adjuvant, an ingredient that boosts the immune system's response to the vaccine. The brand name is Fluad Quadrivalent.
- Recombinant Flu Vaccine: Made using a different process that does not require an egg-grown virus, this vaccine contains three times the antigen of other standard-dose inactivated flu vaccines. The brand name is Flublok Quadrivalent.
If one of these preferred vaccines is not available, it is still recommended that older adults receive any other age-appropriate inactivated flu vaccine rather than delaying vaccination. The key is to get protected, and any flu shot is better than none.
Why the Flu is a Greater Risk for Older Adults
Aging naturally weakens the immune system, a process known as immunosenescence, making older adults more susceptible to infections like the flu. A flu infection can cause severe illness, lead to hospitalization, and exacerbate underlying chronic conditions such as heart disease, diabetes, or lung disease.
- Exacerbation of chronic conditions: For those with existing health issues, the flu can worsen their condition, leading to more serious health events. For instance, the flu increases the risk of a heart attack or stroke in the two weeks following infection for older adults.
- Serious complications: Common and serious flu-related complications include pneumonia, bronchitis, sepsis, and multi-organ failure. These risks underscore the importance of annual vaccination.
- Slower recovery: Unlike younger people who may recover from the flu in a week, older adults can take weeks to regain their strength, and hospitalization can lead to other issues like bedsores and increased family care burden.
High-Dose vs. Standard-Dose Vaccine for Older Adults
Making an informed choice about which flu vaccine to get can be confusing. Here is a comparison to help older adults understand the differences between high-dose and standard-dose vaccines.
| Feature | High-Dose/Adjuvanted Vaccine (for adults 65+) | Standard-Dose Vaccine (for all eligible ages) |
|---|---|---|
| Antigen Content | Contains higher antigen levels (e.g., Fluzone High-Dose has 4x standard) or an adjuvant to boost response | Standard levels of antigen |
| Immune Response | Designed to create a stronger immune response to compensate for weakened immune systems in older adults | Elicits a standard immune response; may be less effective in older adults |
| Protection | Clinical trials show better efficacy in preventing flu and related hospitalizations in adults aged 65+ | Offers valuable protection, but may be less robust for older adults than the specialized versions |
| Side Effects | May have slightly more noticeable, but still mild, side effects due to the stronger immune response (e.g., soreness, aches) | Side effects are generally mild and localized, similar to high-dose versions but potentially less frequent |
| Availability | Available at doctors' offices, pharmacies, and clinics, though stock may vary | Widely available at most vaccination sites |
Conclusion
For older adults, the question of when should older adults have a flu vaccine is best answered with a specific recommendation: target September or October for vaccination. This timing maximizes protection during the peak flu season, which typically occurs in the winter months. Because the immune system's response weakens with age, the CDC recommends that individuals 65 and older receive a higher-potency vaccine, such as a high-dose, adjuvanted, or recombinant flu shot, to ensure a more robust immune defense. However, if these preferred options are not immediately available, any age-appropriate inactivated flu vaccine is preferable to waiting. Annual vaccination is the most important step for older adults to significantly reduce their risk of severe illness, hospitalization, and death from flu and its serious complications, such as pneumonia. By getting vaccinated at the right time with the right vaccine, seniors can proactively safeguard their health and well-being. Learn more about vaccine recommendations for different age groups and populations from the CDC at https://www.cdc.gov/flu/vaccines/vaccinations.html.
