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U.S. Flu Hospitalization Rates Nearly 80% Higher for Black Adults

— Influenza vaccination rates also consistently lower in some minority groups

MedpageToday
A photo of a Black man laying in a hospital bed wearing an oxygen mask.

Influenza-associated hospitalization rates were nearly 80% higher among Black adults compared with white adults from 2009-2010 to 2021-2022, according to a released Tuesday.

These rates were also 30% higher among American Indian/Alaska Native (AI/AN) adults and 20% higher among Hispanic adults compared with white adults, reported Carla L. Black, PhD, of the CDC's National Center for Immunization and Respiratory Diseases, and colleagues.

Furthermore, vaccination coverage for influenza has been "consistently lower among Black, Hispanic, and American Indian and Alaska Native adults since 2010," she noted on a call with reporters.

During the 2021-2022 flu season, vaccination coverage was lower among Hispanic (37.9%), AI/AN (40.9%), Black (42.0%), and other/multiple race (42.6%) adults compared with coverage among white (53.9%) and Asian (54.2%) adults, Black and team said.

While the CDC recommends getting a flu vaccine every year, only about half of all Americans follow this advice, Black noted.

"There are many reasons for disparities in vaccine uptake, including lack of access to healthcare and insurance, missed opportunities to vaccinate, and misinformation and distrust," she added.

According to CDC estimates, influenza has resulted in 9 to 41 million illnesses, 140,000 to 710,000 hospitalizations, and 12,000 to 52,000 deaths per year from 2010 to 2020.

From 2009-2010 to 2021-2022 (excluding 2020-2021 data), the age-adjusted influenza-related hospitalization rates per 100,000 population were:

  • Black adults: 78.2
  • AI/AN adults: 54.6
  • Hispanic adults: 50.3
  • White adults: 43.0
  • Asian or Pacific Islander: 34.5

Interestingly, during the 2011-2012 and 2021-2022 flu seasons, AI/AN adults were hospitalized for influenza more than any other racial group, with age-adjusted rates 2.7 times those in white adults, while these rates among Hispanic adults were 2.1 times that of white adults in 2009-2010 and 2021-2022.

Looking broadly at trends in flu vaccine uptake from the 2010-2011 season through the 2021-2022 season, coverage rose from 40.5% to 49.4% and increased across all racial and ethnic groups, except for AI/AN adults.

Between the 2020-2021 and 2021-2022 flu seasons, coverage dipped by 0.8 percentage points overall, and fell 1.6 percentage points among white adults, while coverage remained "stable" from the 2018-2019 through the 2021-2022 flu seasons across all other racial and ethnic groups, the authors noted.

Common Characteristics of Vaccinated Adults

For the 2021-2022 flu season, vaccine uptake was higher among adults ages 65 and older compared with younger adults across all of the racial and ethnic groups studied. This was also the case for those with health insurance versus those without, those with a personal healthcare provider versus those without, and those who had had a routine medical checkup in the past year versus those who had not.

Compared with white adults, Hispanic adults were less likely to have health insurance, and Hispanic, AI/AN, and multiracial adults and adults of other races were less likely to have a personal healthcare provider and to have had a medical check-up in the past year, the authors noted.

Even among those adults who checked all these boxes, flu vaccine coverage was still higher among white adults compared with Black, Hispanic, AI/AN, and multiracial adults and adults of other races.

Asked whether other factors beyond vaccination status might contribute to Black adults having the highest influenza-associated hospitalization rates, Black explained that "the presence of chronic illnesses contributes to more severe flu outcomes," and some racial and ethnic minorities are more likely to have chronic illnesses. She also noted that crowded housing conditions can also contribute to an individual's risk of hospitalization.

The CDC is continuing to promote vaccination through public awareness campaigns, and encouraging healthcare providers to recommend flu vaccines to their patients and to use culturally appropriate materials that include images that reflect the community and are written in the predominant language of the community.

In addition, programs such as -- which "likely contributed to decreased disparities in COVID-19 vaccination" by using non-traditional settings, such as libraries, barbers shops, and thrifts stores -- might also help to mitigate disparities in influenza vaccination, Black and team wrote.

Study Details

The researchers sought to examine influenza disease severity and vaccination rates by race/ethnicity over a 12- to 13-year period, excluding 2020-2021 influenza-associated hospitalization data because "case counts during this season were too low to calculate rates by race and ethnicity," they noted.

They used the Influenza-Associated Hospitalization Surveillance Network (FluSurv-NET), which tracks confirmed flu-related hospitalizations in certain states, representative of about 8% to 9% of the U.S. population. They also leveraged data from the Behavioral Risk Factor Surveillance System (BRFSS), a telephone survey that collects information on a range of health conditions, including whether respondents received a flu vaccine in the past 12 months.

Limitations to the study included that the FluSurv-NET may not be representative of the entire U.S. population, since it only tracks data in "selected counties." As for BRFSS data, "survey response rates were low and influenza vaccination coverage might differ between survey respondents and nonrespondents," Black and team noted.

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    Shannon Firth has been reporting on health policy as 51˶'s Washington correspondent since 2014. She is also a member of the site's Enterprise & Investigative Reporting team.

Disclosures

The authors disclosed no conflicts of interest.

Primary Source

Morbidity and Mortality Weekly Report

Black CL, et al "Vital Signs: Influenza hospitalizations and vaccination coverage by race and ethnicity -- United States, 2009-10 through 2021-22 influenza seasons" MMWR 2022; DOI: 10.15585/mmwr.mm7143e1.