The Influenza Vaccine in the Aging Population

April 11th 2018
Connor Walker, PharmD Candidate

Influenza infection in the very young, the elderly, and immunocompromised individuals may last longer.

Influenza is an acute respiratory infection that infects humans, birds, and other mammals on a global scale. In many cases, the classic symptoms of myalgia, sore throat, nonproductive cough, and headache are self-limiting, and resolve in 3 to 10 days. However, in the very young, the elderly, and immunocompromised individuals, the infection may last longer.

An article published recently inThe American Journal of Managed Carehighlights this virus’ impact on older populations. Despite receiving more vaccinations than younger age groups, those aged 65 years or older account for the most influenza-related hospitalizations, complications, and deaths. The United States’ vaccination target goal for those aged 65 and older is 90%. However, the current percentage of adults aged 65 years and older who receive the vaccine equates to 65.3%, leaving approximately 35% unprotected. As part of the aging process, the body begins to experience immunosenescence, which is the gradual decline in the immune system. Unfortunately, this decline leaves the elderly more susceptible to infection by influenza.

When given the vaccine, elderly patients tend to mount a lower immune response than younger patients. With seroconversion rates ranging from 17% to 53%, this population is more at risk for infection, even when vaccinated. This creates a need for vaccines with improved seroconversion, and seroprotection in older adults.

To circumvent this poor immune response, vaccine manufacturers offer high-dose, and adjuvanted vaccines, thus provoking a stronger immune reaction. The Advisory Committee on Immunization Practices' 2017-2018 recommendation states that any formulation, standard-dose, or high-dose, trivalent or quadrivalent, unadjuvanted, or adjuvanted, is acceptable in patients aged 65 years and older. Difficulty recommending 1 product over another is due to lack of data in the geriatric population, as most available data available is drawn from younger populations. For elderly patients suffering from an egg allergy, the selection is a bit simpler, 3 FDA-approved vaccines are currently produced without eggs.

The CDC refers readers to many Toolkits available online to help expand vaccine coverage. These resources offer a variety of materials such as campaign materials, programs for improved vaccine use, language resources, and guidance for promoting the vaccine. These resources can be accessed athttps://www.cdc.gov/flu/toolkit/long-term-care/resources.htm.

In addition to these online resources, this article includes a comparison chart of the current available vaccines. Many pharmacists find these charts useful to post near consultation rooms, and vaccine storage areas. Clinicians should encourage all patients, especially those aged 65 years and older, to receive the vaccine as it is proven to reduce morbidity, and mortality.

Connor Walker is a 2018 PharmD Candidate at the University of Connecticut.

Reference

Wilhelm M. Influenza in older patients: a call to action and recent updates for vaccinations.Am J Manag Care. 2018;24(2 Suppl):S15-S24.

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