COVID-19 vaccination much more effective at preventing hospitalization than prior infection only

COVID-19 vaccination is about five times more effective at preventing COVID-related hospitalization than prior infection only, researchers reported on Oct. 29, 2021 in Morbidity and Mortality Weekly Report, a publication of the Centers for Disease Control and Prevention (USA).

“This data provides powerful evidence that vaccinations offer superior protection against COVID-19 than relying on natural immunity alone,” said investigator Shaun Grannis, M.D., M.S., vice president for data and analytics at Regenstrief Institute in Indianapolis, Indiana and professor of family medicine at Indiana University School of Medicine. “Many have been asking if they should get vaccinated if they’ve already been infected — this research shows the answer is yes.”

Notably, the study disclosed that among adults older than 65, mRNA vaccines were about 20 times more effective at preventing hospitalizations than prior infection only.

A VISION Network team gathered and evaluated the data. The Network includes seven organizations that analyze data from U.S. healthcare systems to learn more about COVID-19

The investigators examined records of about 7,400 hospitalized adults aged ≥18 years with COVID-19–like illness. They compared the odds of a positive SARS-CoV-2 test result for unvaccinated subjects with a previous SARS-CoV-2 infection (occurring 90–179 days before COVID-19–like illness hospitalization) and for subjects who were fully vaccinated with an mRNA COVID-19 vaccine 90–179 days before hospitalization who also had no prior documented SARS-CoV-2 infection.

Among subjects whose previous infection or vaccination occurred 90–179 days earlier, the odds of confirmed COVID-among unvaccinated, previously infected adults were 5.49 times higher than the odds among fully vaccinated recipients of an mRNA COVID-19 vaccine with no previous infection

“These findings suggest that among hospitalized adults with COVID-19–like illness whose previous infection or vaccination occurred 90–179 days earlier, vaccine-induced immunity was more protective than infection-induced immunity against laboratory-confirmed COVID-19,” the authors concluded.

“All eligible persons should be vaccinated against COVID-19 as soon as possible, including unvaccinated persons previously infected with SARS-CoV-2.,” they added.