Influenza vaccination was associated with a decreased risk of mortality and recurrent hospitalizations in older adults with cardiovascular disease (CVD), according to findings published in the International Journal of Infectious Diseases.
Researchers in China conducted a retrospective cohort study between January 2014 and December 2019 that analyzed the effects of influenza vaccination among adults aged 60 years and older with CVD. Date used for this study were obtained from the Beijing Elderly Influenza Vaccination (EIV) and the Beijing Urban Employee Basic Medical Insurance (UEBMI) databases. The primary outcomes were in-hospital mortality and recurrent hospitalizations during influenza season, defined as October 1 to March 31.
The study period comprised 6 influenza seasons and included a total of 713,488 patients, of whom 95,060 were vaccinated and 618,428 were unvaccinated against influenza. During this period, mortality occurred among 7822 patients with CVD, and recurrent hospitalizations occurred among 69,459 and 7909 patients with CVD and respiratory diseases, respectively. Of patients with CVD, 13.3% were vaccinated.
Overall, the risk of in-hospital mortality was decreased by 15% among patients with CVD who were vaccinated (odds ratio [OR], 0.85; 95% CI, 0.74-0.99). Stratified by CVD subtype, the researchers noted a 19% and 13% decreased risk of in-hospital mortality among vaccinated patients with ischemic stroke (OR, 0.81; 95% CI, 0.60-1.06) and hemorrhagic stroke (0R, 0.87; 95% CI, 0.60-1.27), respectively. Of note, influenza vaccination was associated with a 41% decreased risk of in-hospital mortality among patients with CVD with no comorbidities.
In regard to the risk for recurrent hospitalization, influenza vaccination was associated with a decreased risk among patients with ischemic heart disease. No significant associations between vaccination and recurrent hospitalization risk were observed among patients with ischemic or hemorrhagic stroke.
Study limitations included the inability to conduct subgroup analyses among patients with hemorrhagic stroke and those who were vaccinated against both influenza and pneumococcal disease due to small sample sizes.
“The protective effect of influenza vaccination on CVD hospitalization outcomes serves as the evidence base to increase the uptake of influenza vaccination among older adults in China,” the researchers concluded.
Pang Y, Liu X, Liu G, et al. Effectiveness of influenza vaccination on in-hospital death and recurrent hospitalization in older adults with cardiovascular diseases. Int J Infect Dis. 2022;122:162-168. doi:10.1016/j.ijid.2022.05.059