From the Guidelines
High dose trivalent flu vaccine, also known as Fluzone High-Dose, is a specialized influenza vaccine that contains 60 μg of HA per vaccine virus, four times the amount of antigen in standard flu vaccines, and is specifically designed for adults 65 years and older. This vaccine is designed to create a stronger immune response in older adults whose immune systems typically respond less robustly to vaccination 1. The higher dose helps compensate for the age-related decline in immune function, providing better protection against influenza in seniors. According to the most recent guidelines, Fluzone High-Dose is one of the two IIV3s approved only for persons aged ≥65 years, and it contains 180 μg total of HA in a 0.5-mL dose 1.
Some key points to consider when administering the high dose trivalent flu vaccine include:
- The vaccine is administered as a single shot, ideally before flu season begins in the fall, and provides protection for the duration of the flu season.
- Side effects are generally similar to standard flu vaccines but may be slightly more common, including mild pain at the injection site, muscle aches, and fatigue that typically resolve within a few days.
- The vaccine is not approved for persons aged <65 years, and other formulations of influenza vaccine are available for younger adults and children 1.
- Clinical studies have shown that the high-dose vaccine is more effective in preventing flu in older adults compared to standard-dose vaccines, although the exact percentage of increased effectiveness may vary depending on the study 1.
It's essential to follow the recommended dosage and administration guidelines for the high dose trivalent flu vaccine to ensure the best possible protection against influenza for older adults 1.
From the Research
Definition of High-Dose Trivalent Flu Vaccine
- High-dose trivalent flu vaccine, also known as IIV3-HD, is a trivalent, inactivated, split-virus influenza vaccine indicated for use in older adults (≥65 years of age) 2.
- It contains 60 µg hemagglutinin of each influenza strain, which is four times the hemagglutinin content of standard-dose influenza vaccines 2.
Characteristics of High-Dose Trivalent Flu Vaccine
- The vaccine has been licensed for use in older adults in the US since December 2009 and in Canada since February 2016 2.
- High-dose trivalent influenza vaccine is safe and well tolerated, and provides superior immune responses compared to standard dose vaccine 3.
- The vaccine efficacy of HD vaccine relative to SD vaccine against any influenza viral type/subtype was 12.6% (95% CI -140.5; 65.8) in the intent-to-treat analysis 3.
Immunogenicity and Efficacy
- Multiple clinical trials have shown that the high-dose trivalent influenza vaccine is more immunogenic and more effective than the standard-dose vaccine in preventing influenza virus infection and its complications in older people 4, 5.
- The vaccine is consistently more immunogenic than standard-dose trivalent vaccine in adults aged ≥ 65 years, with combined HAI geometric mean titer (GMT) ratios approximately 1 month post-vaccination of 1.74 (1.65-1.83) for influenza A/H1N1, 1.84 (1.73-1.95) for influenza A/H3N2, and 1.47 (1.36-1.58) for influenza B 6.
- Trends were similar for A/H3N2 neutralization and anti-neuraminidase antibody titers, and the vaccine also appears more immunogenic in immunocompromised individuals 6.