Characteristics associated with the uptake of influenza vaccination among adults in the United States

Abstract

In 2009, the influenza vaccination coverage level in the United States was 69% in adults 65 years and older but only 32% in adults between the ages of 18 and 64, according to researchers at IHME and the University of Tokyo. Results from the study, “Characteristics associated with the uptake of influenza vaccination among adults in the United States,” show the need for renewed attention to vaccination strategies.

Research objective

Annual influenza epidemics in the US cause illness, hospitalizations, and deaths in Americans and exact a toll on the nation’s health care infrastructure. Influenza vaccination is the most effective method for preventing influenza virus infection and its complications, and the updated Healthy People 2020 objectives to improve the health of Americans include increasing influenza vaccination coverage to 80% among people aged 18 to 64. Healthy People 2010 goals included achieving an influenza vaccination rate of 90% for noninstitutionalized adults 65 years and older and 60% for people aged 18 to 64 with high-risk conditions.

This study was conducted to inform future vaccination strategies by identifying the characteristics of people who are less likely to receive influenza vaccination.

Research findings

The results showed that among 134,101 adults 65 years and older, 69% received an influenza vaccination in the past year. In 286,867 adults aged 18 to 64 years, only 32% received the vaccine. Having health care coverage was the strongest predictor of vaccination in both age groups. People reporting older age, white race, higher education, nonsmoking status, being physically active, having poor physical health, or having a personal history of various chronic conditions were also more likely to have received the influenza vaccine. 

Analytical approach

Researchers used data from the 2009 Behavioral Risk Factor Surveillance System (BRFSS) to estimate adjusted prevalence ratios for receiving the influenza vaccine in the past 12 months. The BRFSS, a large ongoing nationally representative cross-sectional telephone survey of noninstitutionalized adults 18 years and older, was designed to monitor the leading risk factors for morbidity and mortality in the US at the local, state, and national level. Covariates associated with influenza vaccination status were considered, including demographics, socioeconomic status, health behaviors, and physical health status.

Policy implications

These results show that vaccine coverage in the US is related to social position, as well as other health behaviors. The data indicate that current coverage of the influenza vaccine falls far short of both the Healthy People 2010 goals and the updated Healthy People 2020 targets. However, older age and histories of chronic condition are associated with receipt of the vaccine, which suggests that this initiative has achieved some success in the most vulnerable populations.

The authors note that these findings call for renewed attention to vaccination strategies if the Healthy People 2020 goals are to be met, including coordinated immunization campaigns to remind the public of the benefits, safety, and availability of the influenza vaccine. In order to identify pockets of need in the US and counties with low vaccination coverage, novel methodologies, including small area estimation methods, can be used to generate estimates of vaccine coverage at the county level.