News Release 

COVID-19 vaccines are moving fast, but will americans agree to get them?

UCSF-led flu study sheds light on groups most likely to skip shots

University of California - San Francisco

Only one in three U.S. adults received the flu vaccine in 2018, a number that has critical implications for the impending flu season, which threatens to overwhelm medical resources and lead to tens of thousands of deaths at a time when Americans are still reeling from the COVID-19 pandemic.

A new study led by researchers at UC San Francisco has uncovered demographics of those groups who are less likely to receive the flu shot. These findings may inform public health efforts for future COVID-19 vaccines, and raise questions about making both flu and COVID vaccines free of charge and mandatory.

In the study, which publishes in the Journal of General Internal Medicine on Aug. 26, 2020, the researchers evaluated self-reported flu vaccination rates for 2018, which included data from the 2017-18 flu season (61,000 deaths) and 2018-19 season (34,200 deaths). The data was recorded in the Behavioral Risk Factor Surveillance System, an annual national survey of 400,000-plus U.S. adults, conducted by state health departments and the Centers for Disease Control and Prevention.

"To achieve herd immunity, we would need to reach about an 80 percent vaccination rate, but no subgroup in our study exceeded 60 percent," said senior author R. Adams Dudley, MD, MBA, of the UCSF Philip R. Lee Institute for Health Policy Studies and School of Medicine; and University of Minnesota Medical School and Institute for Health Informatics. "While social distancing, mask-wearing and staying away from crowds will mitigate the spread of the flu, a dangerous type of the flu - such as the Spanish flu of 1918 - could result in more than 61,000 fatalities," he said referring to the 2017-18 flu season.

Among the researchers' findings:

Age, insurance status and having a personal doctor were among the biggest determinants of whether a given individual had a flu shot. Some 22.6 percent for those ages 18 to 24 got the flu vaccine, versus 59.3 percent of those over 75. Among those without insurance 16.1 percent were vaccinated, versus 41.6 percent for those with insurance. For patients without a personal doctor 19.4 percent were vaccinated, versus 43.6 percent for those with a personal doctor.

Not having a chronic condition was linked to lower rates. Some 31.6 percent of those with no chronic condition were vaccinated, versus 52.7 percent for people with four or more chronic conditions.

Variation by income group was smaller. Some 33.9 percent for those with a household income of less than $15,000 were vaccinated, versus 41.8 percent of those with an income of more than $50,000.

Rates were lowest in Texas (26.4 percent) and highest in Washington DC (44.2 percent). Other states with low rates were Louisiana (26.4 percent), New York (28 percent), Indiana (28.5 percent) and Tennessee (28.6 percent). Other states with high rates were West Virginia (42.6 percent), North Carolina (41.7 percent), Iowa (40.6 percent) and Pennsylvania (40.3 percent). In California 32.4 percent were vaccinated.

Rates were lower among Blacks and Hispanics (33.9 percent and 28.9 percent) than whites and Asians (41.5 percent and 38.3 percent).

Men were less likely than women to receive the flu shots (36.7 percent versus 41.6 percent).

To boost vaccination rates, both long-term and short-term interventions are needed, said first author Brandon Yan, a third-year medical student at UC San Francisco. "We need a concerted public health campaign that includes public health officials, health care providers and local communities, and reaches those groups most at risk for not getting vaccinated. And we need a proactive primary care outreach strategy to address patient concerns and provide information on how and where to get vaccinated."

In the long-term the goals are loftier, said Yan, and include making the vaccines more accessible, such as expanding availability in grocery store pharmacies, and making them free of charge for those who are uninsured. "The ongoing pandemic also raises the issue of whether the flu vaccine and the future COVID-19 vaccine should be mandated," he said. "While a federal mandate may be difficult politically, private organizations like colleges and employers could make attendance and employment contingent on getting up-to-date with vaccines."

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Co-Author: Frank Sloan, PhD, of Duke University, Durham, N.C.

About UCSF: The University of California, San Francisco (UCSF) is exclusively focused on the health sciences and is dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. UCSF Health, which serves as UCSF's primary academic medical center, includes top-ranked specialty hospitals and other clinical programs, and has affiliations throughout the Bay Area. Learn more at ucsf.edu, or see our Fact Sheet.

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