Understanding the Aging Immune System (Immunosenescence)
As we age, our immune system naturally weakens, a process called immunosenescence. This decline makes older adults more susceptible to infections like influenza and reduces their response to standard-dose vaccines.
The Enhanced Need for Protection in Older Adults
Adults 65 and older face a significantly higher risk of severe flu complications, hospitalization, and death. The CDC notes that a large percentage of flu-related hospitalizations occur in this age group. Underlying health issues and frailty contribute to this vulnerability, necessitating specialized vaccines for better protection.
The Three Preferred Flu Vaccines for Seniors
The CDC recommends three types of injectable flu vaccines for adults 65 and older, offering stronger protection than standard options.
High-Dose Flu Vaccine (Fluzone High-Dose)
High-dose vaccines, such as Fluzone High-Dose, contain four times the antigen of a standard shot. This higher antigen level aims to create a stronger immune response in older adults, improving flu protection.
Adjuvanted Flu Vaccine (Fluad)
The adjuvanted vaccine, Fluad, includes an adjuvant (MF59) to boost the immune response to the antigen. This provides a stronger, longer-lasting response with the same antigen amount as a standard shot. MF59 was approved for use in the U.S. in 2016 after being used in Europe.
Recombinant Flu Vaccine (Flublok)
Flublok, a recombinant vaccine, is egg-free and contains three times the antigen of a standard dose. This non-egg-based technology provides a strong immune response, making it suitable for those with severe egg allergies.
Comparison of Senior Flu Vaccines
| Feature | High-Dose (Fluzone High-Dose) | Adjuvanted (Fluad) | Recombinant (Flublok) |
|---|---|---|---|
| Mechanism | Contains 4x the antigen of a standard dose. | Contains an adjuvant (MF59) to boost immune response. | Contains 3x the antigen of a standard dose. |
| Antigen Source | Egg-based manufacturing process. | Egg-based manufacturing process. | Non-egg-based recombinant technology. |
| Side Effects | May cause slightly more pronounced temporary side effects (pain, redness, headache). | May cause slightly more pronounced temporary side effects (pain, redness, headache). | Similar side effects profile to standard flu shots. |
| Age Approval | Approved for adults 65 years and older. | Approved for adults 65 years and older. | Approved for adults 9 years and older, recommended for 65+. |
Optimal Timing for Senior Vaccinations
Immunity from flu shots can decrease over time, potentially faster in older adults. The CDC advises adults 65 and older to get their flu shot in September or October to ensure protection throughout the flu season, which typically peaks later. Getting vaccinated too early might lead to reduced protection later in the season.
Addressing Common Concerns and Contingencies
Injectable flu vaccines use inactivated viruses and cannot cause the flu. Mild side effects like soreness or fever are normal signs of an immune response, not the flu. If a preferred vaccine is unavailable, seniors should get any other age-appropriate flu vaccine, as some protection is better than none.
A Crucial Step for Healthy Aging
Understanding why over 65 have a different flu vaccine is vital for healthy aging. These specialized vaccines are key to preventing severe illness in a vulnerable population. Eligible older adults should receive one of these enhanced vaccines annually to reduce their risk of complications. Consult your healthcare provider or the Centers for Disease Control and Prevention website for the latest information and guidance.
