Efficacy of the Adjuvanted Influenza Vaccine Compared With the High-Dose for Older People

Abstract

Reported cases of influenza are increasing among those 65 years of age and older. Older people may be less likely to get sick from influenza, but they are at an increased risk for influenza complications, hospitalizations, and deaths. Influenza infections and complications have become even more of a concern for this population recently because of the impact of COVID-19. Evidence exists of waning immunity in older people because of immunosenescence. Enhanced vaccines were manufactured to help boost the immune response more than what is seen with standard influenza vaccines in older people. There are currently two enhanced vaccines specifically approved for persons 65 years of age and older: the adjuvanted quadrivalent influenza vaccine (aQIV) and the high-dose quadrivalent influenza vaccine (HD-QIV). Based on current data, enhanced vaccines may be of more benefit for those 65 years of age and older. This is reflected in the most recent recommendations from the Advisory Committee on Immunization Practices (ACIP) for people 65 years of age and older, which advise to not delay vaccination and receive either a high-dose or adjuvanted influenza vaccine. There is currently no preference given over any enhanced vaccine in this age group. Influenza vaccinations have been found to reduce the risk of hospitalization from influenza complications, such as cardiovascular complications like strokes and myocardial infarction, in those 65 years of age and older, specifically those with co-existing cardiovascular disease. Immunizations are the primary prevention strategy, and we should ensure proper vaccine administration to provide maximal efficacy and reduce the chances of influenza complications.