Adult flu shots have slumped in states with low COVID-19 vaccination rates, suggesting that COVID-19 vaccination behavior may have spilled over to flu-vaccine behavior, new research indicates.
University of California, Los Angeles researchers point to declining trust in public health agencies caused by controversy over COVID-19 vaccines as a possible reason for the falloff in flu vaccination.
"It is alarming that controversy surrounding COVID-19 vaccination may be undermining separate public health efforts that save thousands of lives each year," said study lead author Dr. Richard Leuchter. He's a resident physician at UCLA Health and the David Geffen School of Medicine.
The analysis of U.S. Centers for Disease Control and Prevention data through January 2022 showed that adult flu vaccination rates remained relatively stable in all states during the first flu season of the pandemic (2020-2021), before widespread availability of COVID-19 vaccines.
But flu shot rates in the second flu season of the pandemic (2021-2022) - when COVID-19 vaccines were widely available - fell from about 44% to around 39% in states with below-average rates of COVID-19 vaccination.
In contrast, flu shot rates in states with the highest rates of COVID-19 vaccination rose from 49% to nearly 53%, according to the study. The findings were published June 15 in the New England Journal of Medicine as a letter to the editor.
Rates of full COVID-19 vaccination varied from 50% in Alabama to 81% in Rhode Island through January 2022. Flu vaccination rates through January of the 2021-2022 flu season also varied, ranging from 31% in Mississippi to 59% in Connecticut.
A state's average COVID-19 vaccination rate could explain 60% of the variation in its flu vaccination rate, which "is compelling evidence that the vaccination behaviors for flu and COVID-19 vaccines are inextricably linked," Leuchter said in a university news release.
The findings may indicate that low uptake of COVID-19 vaccination has spilled over into flu vaccination, the researchers suggested.
"Many Americans who never before declined a routine, potentially life-saving vaccine have started to do so. This supports what I have seen in my clinical practice and suggests that information and policies specific to COVID-19 vaccines may be eroding more general faith in medicine and our government's role in public health," Leuchter said.
Something called "belief generalization" may be a factor, he noted.
"Much as someone's decision to wear or forgo a mask in public during the early pandemic was linked with their more general beliefs through the idea of 'belief signaling,' we propose that 'belief generalization' may account for COVID-19 vaccine-specific opinions being generalized to other vaccines," Leuchter said. "People who feel compelled to oppose or support COVID-19 vaccines may feel that they should in turn oppose or support other vaccines."
The findings are cause for alarm, and warrant immediate research into the causes, according to the study authors.
Learn more about flu shots at the U.S. Centers for Disease Control and Prevention.
SOURCE: University of California, Los Angeles, news release, June 15, 2022