Study offers reassurance of flu vaccination during COVID-19 pandemic
Influenza vaccination did not increase the incidence of COVID-19 or worsen outcomes related to the disease, researchers reported.
Encouraging data that suggest efforts to curb the COVID-19 pandemic — including masking and physical distancing — have led to a global decline in influenza cases, but there are still concerns that the influenza season could stress hospitals that are already strained because of the pandemic.
“Taking everything into consideration, our patients should be encouraged to receive their flu shot this fall,” Joe G. Zein, MD, PhD, of the pulmonology department at the Cleveland Clinic, told Healio Primary Care.
Zein and colleagues analyzed data from 13,220 patients in Florida and Ohio who were tested for COVID-19 between March 8 and April 15 — including 4,138 who received unadjuvanted influenza vaccination for the 2019-2020 season (mean age, 61.5 years; 39.9% men; 73.7% white) and 9,082 who did not (mean age, 49.3 years; 44.6% men; 65.9%, white).
In an unadjusted analysis, Zein and colleagues found that patients vaccinated against influenza were less likely to test positive for SARS-CoV-2. Among patients with a positive SARS-CoV-2 test, those who were vaccinated against influenza last season were more likely to be hospitalized and consequently, more likely to be admitted to the ICU and die during hospitalization.
Using an overlap propensity score weighting method, the researchers found that influenza vaccination was unrelated to the incidence of SARS-CoV-2 infection (adjusted OR = 0.79; 95% CI, 0.62-1). Among the 1,434 patients who had COVID-19, the 309 who also received influenza vaccination had no higher risk for hospitalization (aOR = 1.29; 95% CI, 0.72-2.31), ICU admission (aOR = 0.65; 95% CI; 0.22-1.79) or hospital mortality (aOR = 0.98; 95% CI, 0.39-2.43).
Zein stressed that influenza vaccination is safe.
“Extra precautions have been put into place to ensure the safety of patients and caregivers as flu vaccinations are provided to our patients” he said.
He encouraged the scientific community to “continue to collect data on both infections — and vaccination — and prospectively monitor the convergence of seasonal influenza and COVID-19.”