Which Flu-Shot Should Seniors Select?

High dose influenza vaccines were reported to be more effective than a standard-dose flu shot in protecting seniors

older man walking arounf the lake

Seniors experience the most health complications during the flu season.

In recent years, it’s estimated that between 71 to 85 percent of seasonal flu-related hospitalizations and deaths have occurred in people 65 years and older.

It's hard to know which flu shot is best for seniors.

In a new clinical study, a high-dose influenza vaccine was reported to be 38 percent more effective than a standard-dose vaccine, according to a study of senior patients published yesterday in the Journal of Infectious Diseases.  

This study’s main result, a relative vaccine effectiveness (rVE) of the high-dose vaccine was 38% (95% CI, -5-65%) against laboratory-confirmed influenza is consistent with the randomized clinical trial (RCT) estimate of 24.2% (95% CI, 9.7%-36.5%) against laboratory-confirmed influenza-like illness.

In contrast, for influenza-related and pneumonia-attributed hospitalizations, low-dose, influenza vaccine reported a relative efficacy of only 2% (95% CI, -40%- 32%).

Seasonal influenza epidemics have a substantial public health and economic burden in the USA. On average, more than 200,000 people are hospitalized and upwards of 49,000 people are estimated to die each year from respiratory and circulatory complications, associated with seasonal influenza virus infections.

Previous observational clinical studies reported various rVE, but differed by study design details such as inclusion/exclusion criteria, timeframe, and outcomes, warranting additional examination of the effectiveness of the HD vaccine as necessary guidance for clinical practice and public policy, especially for Veterans.

This study was a retrospective cohort study among senior Veterans Health Administration (VHA) patients during the 2015-2016 season, against influenza- or pneumonia-associated hospitalization.

This study focused on three categories of outcomes:

  • influenza- or pneumonia-associated with a hospital or outpatient visit,
  • all-cause hospital or outpatient visit,
  • any medical encounter with a positive influenza test.

“Since our senior patients are the most vulnerable to influenza complications, it is important to protect them with the most effective vaccine possible each year,” Chris Felton, PharmD MTM Clinical Pharmacist at Brookshire Grocery Company.

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“This study validates protocols that we have in place to ensure seniors understand the benefit of choosing Flublok or Fluzone HD vaccines when they come in to get their flu shot.  Education is critical because we cannot assume that patients know the difference between the vaccines”, explained Felton.

The VHA is the single largest integrated health care system in the USA, delivering care to military veterans at 144 medical centers, 1,203 community-based outpatient clinics, and 300 Veteran Centers.

As of 2015, there were over 6 million patients with healthcare service records in the VHA.

Immunization providers should check the FDA approved prescribing information for 2017–18 influenza vaccines for the most complete and updated information.

In 2009, the Food and Drug Administration (FDA) licensed an injectable high-dose inactivated trivalent influenza vaccine, Fluzone, which contains 4 times more influenza hemagglutinin antigen than standard-dose influenza vaccines.

In 2013, the Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention (CDC) unanimously recommended Flublok for seniors, including those with egg allergies.

Most pharmacies offer several FDA approved flu vaccines.

The flu shot cost varies depending on your insurance and which state you live. The CDC Vaccine Price List provides the private sector vaccine prices for general information.

Flu vaccine discounts can be found here.

This research was funded by Sanofi Pasteur. Declaration of Authors Competing Interests JKL, EWT, and AC are employees of Sanofi Pasteur. JTS is an employee and holds equity in Precision Health Economics, which provides consulting services to the life sciences industry. SG is a consultant for Sanofi, Seqirus, Novartis, Merck, Longevoron; DW and KJR report personal fees and non-financial support from Sanofi-Pasteur; YYX received research funding from Sanofi-Pasteur.