Previous COVID-19 infections provided some protection against delta variant, CDC study finds

Findings do not apply to omicron surge
Virus Outbreak Washington
Posted at 1:00 PM, Jan 19, 2022

A new study released Wednesday by the Centers for Disease Control and Prevention says people who suffered a previous COVID-19 infection were protected from another infection or hospitalization during the delta variant surge late last year.

However, the CDC warned that the study was conducted prior to the arrival of the omicron variant and said that the study's findings "cannot be applied to the current omicron wave."

The study, which was conducted throughout 2021 in New York and California, looked at four groups of people — those unvaccinated without a previous infection, those unvaccinated with a previous infection, vaccinated people without a previous infection and vaccinated people with a previous infection.

It found that after a COVID-19 infection, a person's chances of catching the virus again or becoming hospitalized from the virus dropped, even as the delta variant spread. That held true even among those who were unvaccinated.

The study, however, also found that those who had both been vaccinated and suffered a previous infection had much higher degrees of protection compared to the three other groups.

The CDC also said in its findings that it could not apply the findings to the current surge caused by the omicron variant because that variant behaves differently than delta. The health agency still urges everyone over the age of 5 to seek out vaccination, as the shots are proven to be safe and have mostly mild side effects.

"Viruses are constantly changing, including the virus that causes COVID-19. These changes occur over time and can lead to the emergence of new variants that have new characteristics, including ones that impact the level of immunity vaccination and/or prior infection can provide," the CDC said in a press release. "The level of protection offered by vaccination and surviving a previous infection changed during the study period. Vaccination remains the safest strategy for protecting against COVID-19."