Fluzone High-Dose Quadrivalent is the only licensed high-dose inactivated flu vaccine. It contains 4 times the antigen (the part of the vaccine that helps the immune system build up protection against flu viruses) compared with standard-dose inactivated flu vaccines. As reasons for the preference, the healthcare providers cited superior efficacy compared with a standard-dose flu shot and total years of real-world data, according to the survey findings, which were released on June 22.
High-Dose Flu Shot More Effective Than Standard Dose in Preventing Infection and Hospitalization
Clinical trials published in The New England Journal of Medicine in 2014 comparing Fluzone High-Dose with standard-dose Fluzone found that the high-dose version created a stronger immune response (higher antibody levels) in people 65 years and older. The high-dose shot was 24 percent more effective in preventing flu infection relative to a standard-dose vaccine, the trials found. The high-dose vaccine also appears to be more effective in keeping people who do get the flu out of the hospital, according to research conducted during the 2013–14 flu season among more than 38,000 residents of 823 nursing homes in 38 states. The research found that people 65 years and older who got Fluzone High-Dose had a lower risk of hospital admission compared with people in that age group who got standard-dose Fluzone, especially those living in long-term care facilities. “Those studies were done with what’s called a trivalent vaccine — it covered two A strains and one B strain,” says Paul Auwaerter, MD, clinical director of the division of infectious diseases at Johns Hopkins Medicine in Baltimore. The high-dose vaccine available for the 2022-23 flu season will be quadrivalent, meaning it covers four flu strains — two A strains and two B strains — he explains. Although predicting the efficacy of any flu shot in a given year is difficult because every flu season is different, the high-dose flu vaccine has been shown in studies to prevent more infections and save lives, says Dr. Auwaerter. These healthcare providers were presented with three different vaccine options in a blinded format: Fluzone (High-Dose Quadrivalent), Fluzone Quadrivalent (Influenza Vaccine), and Fluad Quadrivalent (Influenza Vaccine, Adjuvanted), and asked a series of questions about their preferences. Nearly 74 percent of survey respondents said they would recommend a vaccine with the clinical profile of Fluzone High-Dose Quadrivalent for patients 65 years of age and older over another flu vaccine designed for this population, or over a standard-dose influenza vaccine.
People 65 and Older Are at Higher Risk for Serious Flu Complications
Why do people 65 and older benefit from a higher-dose flu shot? “We know that as people age, especially in people 65 and older, their immune systems don’t respond as vigorously as they did at younger ages. This group is especially prone to more severe or complicated influenza,” says Auwaerter, and is more likely to require hospitalization. The idea behind high-dose vaccines is to try to stimulate the immune system to generate higher levels of antibodies, he adds. In recent flu seasons, the CDC estimates that between 70 and 85 percent of seasonal flu-related deaths and between 50 and 70 percent of seasonal flu-related hospitalizations occurred in people 65 years and older. “Many of my patients who are 65 and older have wanted to get this flu shot because if you’re going to get a flu shot at all, why not get one that has a track record for producing better immune responses, providing more protection against influenza, and [resulting in] less severe disease?” says Auwaerter. Side effects for the high-dose flu shot are similar to those of the standard-dose flu shot, he says, with most people having minimal issues. Public health experts agree that it’s safe to get a flu shot (either a high-dose or standard dose) at the same time as a COVID-19 vaccine or booster.
CDC Advisory Committee Recommends Use of High-Dose Vaccines for People 65 Years and Older
In a June 22 meeting, the Advisory Committee on Immunization Practices (ACIP) voted to recommend the use of high-dose vaccines (Fluzone High-Dose and Flublok recombinant vaccine) or adjuvated flu vaccine (Fluad vaccine) over standard-dose vaccines for seniors. An adjuvant is an ingredient added to a vaccine that helps create a stronger immune response. “Previously, the CDC had said that seniors could get the high dose, but that any dose would do,” says Auwaerter. The CDC director must approve the ACIP’s recommendation in order for it to become policy, which is likely to happen, Auwaerter says.
Will There Be Enough High-Dose Flu Shot to Meet Demand?
The CDC recommends that almost everyone 6 months and older get a seasonal flu vaccine each year, ideally by the end of October. Because immunity may decrease more quickly in older people, it is especially important that people 65 and older are not vaccinated too early — September and October are generally good times, per the agency. “I think it makes sense for people 65 and older to get a high-dose flu shot, and I am hoping that if this becomes CDC policy that there will be enough supply for people to follow the recommendation,” says Auwaerter. Typically, when the CDC makes a new recommendation, there’s not always an idea fit between supply and demand, he explains. “Certainly, for a motivated senior who wants to get the recommended high-dose flu vaccine, you can call around and see if [different vaccination locations] have it on hand,” says Auwaerter. Should you put off getting the high-dose flu vaccine if your doctor’s office or pharmacy doesn’t have it in stock? Both Auwaerter and the CDC agree that if people 65 and older don’t have access to one of the high-dose or adjuvanted vaccines, they should get a standard-dose flu vaccine instead.
