HealthDay News — Children who have received a flu shot are less likely to have symptomatic COVID-19 or severe disease, according to a study recently published in Cureus.
Anjali Patwardhan, MD, and Adrienne Ohler, PhD, from the University of Missouri in Columbia, examined the effect of influenza and pneumococcal vaccines on the disease course among patients infected with SARS-CoV-2 aged 20 years and younger who visited Arkansas Children’s Hospital System between Feb. 1 and Aug. 30, 2020.
The researchers found that viral interference may have played a role in the flu and COVID-19 twindemic. Comparing SARS-CoV-2-positive patients who had been vaccinated vs those who had not been vaccinated showed that patients who were vaccinated had lower odds of having symptomatic diseases (odds ratio [OR], 0.714). Patients who received the pneumococcal vaccine also had lower odds of having symptomatic disease than those who were unvaccinated (OR, 0.482).
Compared with patients who were not vaccinated, patients who received a flu shot had lower odds of having COVID-19 respiratory symptoms (OR, 0.678). Patients vaccinated for influenza and pneumonia had lower odds of severe disease than those not vaccinated (ORs, 0.672 and 0.412, respectively).
“It is known that the growth of one virus can be inhibited by a previous viral infection,” Patwardhan said in a statement. “This phenomenon is called virus interference, and it can occur even when the first virus invader is an inactivated virus, such as the case with the flu vaccine.”