Research Finds Pneumococcal Vaccination Coverage Varies Significantly By Region

A recent study examining pneumococcal vaccination coverage in metropolitan statistical areas (MSAs) found that coverage varies significantly and identified regional factors associated with pneumococcal vaccination.

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Invasive pneumococcal disease causes significant morbidity and mortality, with an estimated 8 cases per 100,000 adults aged 19 to 64 years of age and 24 cases per 100,000 adults aged 65 and older in the United States in 2019. The annual estimated cost of pneumococcal disease is between $1.9 and $5 billion, with a majority of these costs accruing in unvaccinated adults.

Immunization is the key preventive measure, although vaccination rates are not optimal. In 1997, the CDC Advisory Committee on Immunization Practices (ACIP) began recommending pneumococcal vaccines for adults aged 19 to 64 years of age with chronic or immunocompromising conditions, and the guidelines have continued to be updated as new vaccines are approved and research develops.

In 2021, the ACIP guidelines for adults aged 19 to 64 years of age were updated following the FDA approval of new pneumococcal vaccines and recommended a 20-valent conjugate vaccine (Prevnar 20; Wyeth Pharmaceuticals LLC) alone or pneumococcal 15-valent conjugate vaccine (Vaxneuvance; Merck) followed by a 23-valent polysaccharide vaccine (Pneumovax 23; Merck) for adults with certain underlying medical conditions. Despite these recommendations, pneumococcal vaccination coverage rates among United States adults aged 19 to 64 with chronic or immunocompromising conditions remains lower than the CDC Healthy People 2020 target of 60%, with recent estimates ranging from 10.5% to 29.2%.

Individual-level factors associated with higher likelihood of pneumococcal vaccination in this population have been well established, but there are limited published data on regional variations. The objective of the current study was to examine these regional variations among adults with underlying conditions, and to identify regional factors associated with pneumococcal vaccination.

Investigators primarily used the combined IBM Watson Health MarketScan Commercial and Medicare Supplemental databases and defined the study population as adults aged 19 to 64 years of age who were newly diagnosed with a chronic or immunocompromising condition in 2013.

A total of 255,330 adults met all inclusion criteria and were included in the analysis. Patients had a mean age of 48.5 years and 55.7% were aged 50 years or older. Additionally, 66.6% were White, 14.7% were Hispanic, and 10.3% were Black. MSA was the most granular geographical level available in the databases and provided a large number of patients with conditions of interest for comparison, the investigators said.

According to the study, the proportion of newly diagnosed adults receiving a pneumococcal vaccine during the follow-up period was 13.4% across MSAs, but there was substantial variation. The 3 MSAs with the lowest pneumococcal vaccination coverage values were Ames, Iowa (0.0% vaccinated); Cheyenne, Wyoming (0.0% vaccinated); and California-Lexington Park, Maryland (3.1% vaccinated). The 3 MSAs with the highest coverage were Ann Arbor, Michigan (34% vaccinated); Jefferson City, Missouri (32.2% vaccinated); and Bismarck, North Dakota (30.8% vaccinated).

Analysis indicated that MSAs with higher proportions of adults aged 50 years or older, adults with a health maintenance organization (HMO) health plan, or who had received an influenza vaccine during the follow-up period had higher pneumococcal vaccination coverage. Notably, a 10% increase in the proportion of adults aged 50 years or older was associated with a 1.2% increase in pneumococcal vaccination coverage. Similarly, 10% increases in the proportion of adults receiving an influenza vaccination or being covered under an HMO plan were associated with a 1.1% or 0.8% increase in pneumococcal vaccination coverage, respectively.

The findings could be useful in several key ways, the investigators noted. Firstly, MSAs with low pneumococcal vaccination coverage may recognize low coverage and identify appropriate interventions to increase coverage. Additionally, by examining the number of patients and costs associated with preventable pneumococcal disease in MSAs, health care professionals and policy makers may justify targeted reallocation of resources to MSAs that could most benefit.

REFERENCE

Liu J, Dunham LS, and Johnson KD. Regional factors associated with pneumococcal vaccination coverage among US adults with underlying chronic or immunocompromising conditions. Hum Vaccin Immunother, 19:1. doi:10.1080/21645515.2023.2194779