Past history of vaccination increased likelihood of getting the flu shot

New research from McGill and McMaster Universities suggests COVID-19 fostered an increased interest among adults to get the flu vaccine during the first year of the pandemic, and that those who were most likely get to the flu shot had a past history of vaccination.

The findings were published online in December in the journal Vaccine.

“COVID-19 likely had a significant impact on health-seeking behaviours and health risk perceptions among older adults, which led us to evaluate how influenza vaccination uptake changed during the pandemic relative to the pre-pandemic period,” said Dr. Giorgia Sulis, an infectious disease epidemiologist and postdoctoral fellow in the Department of Epidemiology, Biostatistics and Occupational Health at McGill University.

The research team, which involved investigators across the country including COVID-19 study lead Dr. Parminder Raina at McMaster University, analyzed self-reported data on flu vaccine uptake and willingness to receive a COVID-19 vaccine from approximately 23,000 participants enrolled in the Canadian Longitudinal Study on Aging (CLSA)..

The researchers found that having a history of influenza vaccination was the strongest predictor of influenza vaccine uptake during the 2020-21 season and was also strongly associated with participants’ willingness to receive a COVID-19 vaccine. 

“Older adults are at higher risk of serious illness from the virus that causes COVID-19 and the influenza virus. Interestingly, our research shows that individuals who were concerned about COVID-19 were more likely to get the flu shot in the 2020-21 season and were also more likely to be willing to receive a COVID-19 vaccine,” Sulis said.

“COVID-19 has increased vaccine literacy within the population,” said Dr. Parminder Raina lead principal investigator of the CLSA and the scientific director of the McMaster Institute for Research on Aging.

“In 2020, we saw an increased likelihood of influenza vaccine uptake within the older adult population, which was linked to worries about COVID-19.”

While most vaccination campaigns focus on sociodemographic characteristics, such as age and sex, these findings suggest a new approach may be warranted. 

“Our study provides insights into a comprehensive range of characteristics associated with influenza vaccine uptake and willingness to get vaccinated during these unprecedented times. Our analysis can be used to inform and improve upon current strategies for improving vaccination,” said Dr. Nicole Basta, an infectious disease epidemiologist and Associate Professor of infectious disease epidemiology at McGill.

“Future efforts should explore approaches to identifying and building trust with those who have no recent history of accessing flu vaccination services.”

Funding for the CLSA COVID-19 Questionnaire Study, a sub-study of the CLSA, was provided by the Juravinski Research Institute, McMaster University, the McMaster Institute for Research on Aging, the Nova Scotia COVID-19 Health Research Coalition and the Public Health Agency of Canada.

The overall CLSA research platform is funded by the Government of Canada through the Canadian Institutes of Health Research and the Canada Foundation for Innovation.