Vaccination Plus Prior Infection Best Defense Against COVID

THURSDAY, Jan. 20, 2022 (HealthDay News) -- Think your prior bout of COVID shields you enough from another encounter with the coronavirus? New research suggests that adding in vaccination is still your best bet.

A combination of vaccination and prior infection offers the most optimal protection against infection with COVID-19, a new government study shows.

Researchers analyzed data on infections in New York and California in the summer and fall of 2021 and found vaccinated people with a past COVID infection had the best protection against the disease. The data was published Jan. 19 in Morbidity and Mortality Weekly Report, a publication of the U.S. Centers for Disease Control and Prevention.

The agency noted that the study was conducted before Omicron became the dominant variant and before many people had received booster doses, and that it did not include information on the severity of past infections or look at the risk of severe illness or death from COVID-19. The Omicron variant now accounts for more than 99% of all U.S. COVID cases, CDC data shows.

Vaccination "remains the safest strategy" to prevent COVID-19 and "all eligible persons should be up to date with COVID-19 vaccination," added the study authors, who were led by Tomás León, from the California Department of Public Health.

A number of experts said they were concerned about how the study results might be interpreted.

“The bottom line message is that from symptomatic COVID infection you do generate some immunity,” immunologist E. John Wherry, of the University of Pennsylvania, told the Associated Press. “But it’s still much safer to get your immunity from vaccination than from infection.”

Relying only on a past infection for protection involves too many unknowns, warned Ali Ellebedy, an immunologist at Washington University in St. Louis.

“There are so many variables you cannot control that you just cannot use it as a way to say, ‘Oh, I’m infected then I am protected,’” Ellebedy told the AP.

More information

Visit the U.S. Centers for Disease Control and Prevention for more on COVID vaccines.