Influenza, commonly known as the flu, poses a health risk each year, particularly for individuals aged 65 and older. This age group faces a higher likelihood of developing severe complications from the flu, which can lead to hospitalization or even death. Annual flu vaccination is an important step in protecting against these serious outcomes. While a flu shot is recommended for nearly everyone aged six months and older, the approach to vaccination changes for older adults due to unique physiological considerations.
Why Flu Vaccination is Different for Seniors
The immune system undergoes changes with age, a process called immunosenescence. This natural decline in immune function can reduce the body’s ability to mount a strong response to infections and vaccines. As individuals age, their immune cells may become less effective at recognizing and fighting off viruses, including the influenza virus. This diminished immune response means that standard flu vaccines might not provide the same level of protection for older adults as they do for younger individuals.
Immunosenescence affects both innate and adaptive immunity, leading to a reduced capacity to produce antibodies and a less robust T-cell response. These changes can result in lower antibody levels after vaccination and a quicker decline in vaccine-induced protection over time. Specialized flu vaccine formulations have been developed to overcome these age-related immune challenges and enhance the protective response in people aged 65 and older.
Specialized Flu Vaccine Options
To address the challenges of immunosenescence, specific flu vaccine formulations are recommended for individuals 65 years and older. These specialized vaccines aim to stimulate a stronger immune response compared to standard-dose options. The three main types are the High-Dose Quadrivalent, Adjuvanted Quadrivalent, and Recombinant Quadrivalent flu vaccines. Each is designed with unique features to enhance protection.
High-Dose Quadrivalent Flu Vaccine
The High-Dose Quadrivalent Flu Vaccine contains four times the amount of antigen found in a standard flu shot. Antigens trigger an immune response; this increased dosage aims to provoke more robust antibody production in older adults. This vaccine is produced using an egg-based process and provides protection against two influenza A and two influenza B virus strains. Studies indicate that this higher antigen load can lead to higher antibody levels in vaccinated seniors.
Adjuvanted Quadrivalent Flu Vaccine
The Adjuvanted Quadrivalent Flu Vaccine includes an ingredient called an adjuvant. The adjuvant creates a stronger and longer-lasting immune response by prompting the immune system to react more vigorously. This vaccine is manufactured using an egg-based process and targets two influenza A and two influenza B virus strains. The adjuvant acts as an immune system booster for older adults.
Recombinant Quadrivalent Flu Vaccine
The Recombinant Quadrivalent Flu Vaccine uses a different manufacturing method that does not involve eggs. Instead, it uses recombinant DNA technology to produce hemagglutinin (HA) proteins in insect cells. This production method ensures a precise amount of HA protein for each of the four influenza strains (two A and two B types). This vaccine contains three times the amount of HA compared to standard vaccines, providing a strong stimulus for the immune system without the use of eggs or adjuvants.
Making Your Vaccination Choice
Health authorities preferentially recommend these higher-dose or adjuvanted flu vaccines for individuals aged 65 and older. This recommendation is based on evidence suggesting these specialized vaccines offer potentially greater effectiveness in this age group compared to standard-dose options. If one of these preferentially recommended vaccines is not available, receiving a standard-dose unadjuvanted inactivated flu vaccine is still beneficial and advised. Any flu vaccine approved for your age group is better than none.
Common side effects for these specialized vaccines are mild and temporary, similar to those experienced with standard flu shots. These may include soreness, redness, or swelling at the injection site, as well as headache, muscle aches, or fatigue. Symptoms usually resolve within one to three days after vaccination. While high-dose vaccines may cause slightly more pronounced side effects due to their stronger immune response, these are manageable.
The best time for most adults, especially those 65 and older, to get vaccinated is in September or October. Vaccinating too early might lead to decreased protection later in the flu season. Vaccination should continue throughout the flu season as long as influenza viruses are circulating. Flu vaccines are widely available at various locations, including doctor’s offices, pharmacies, and community clinics. Medicare Part B covers the cost of the flu vaccine for beneficiaries.