SAN FRANCISCO, Calif. (KRON) – A new study from the Centers for Disease Control and Prevention (CDC) suggests that vaccines offer much stronger immunity to COVID-19 than natural immunity.

Researchers analyzed data from nearly 200 hospitals across the country, and concluded that COVID vaccines still offer better protection than a previous COVID infection. Specifically, the CDC report found that unvaccinated adults with previous COVID infection were 5.49 times more likely to be re-infected than fully vaccinated individuals with no previously documented infection.

Doctors say this study contains good information for vaccine holdouts, or people looking to gain immunity by simply getting sick with COVID-19. The latter, experts say, is especially risky, because it can lead to hospitalization or death. 

Marin County public health officer Dr. Matt Willis says people who are protected through the vaccine get sick less frequently, and are less likely to contract severe illness. Non-vaccinated people who have already been infected with COVID-19 should also understand that the amount and quality of those antibodies is hard to measure, he says.

Gaining immunity through the vaccine, meanwhile, has been proven to work through clinical trials, Dr. Willis notes.

The results of the CDC's study, published Friday, also indicate an even higher benefit for certain age groups or recipients of specific vaccines.

"In this study, the benefit of vaccination compared with infection without vaccination appeared to be higher for recipients of Moderna than Pfizer-BioNTech vaccine, which is consistent with a recent study that found higher vaccine effectiveness against COVID-19 hospitalizations for Moderna vaccine recipients than for Pfizer-BioNTech vaccine recipients," the study noted.

Vaccination benefits also "trended higher" for those over 65 than for vaccinated individuals between between 18 and 64 years of age, the CDC said. Re-infection odds were still higher, however, for unvaccinated individuals who had been previously infected, among both age groups.

The CDC said additional research is needed for further results regarding protection across different demographic groups, and protection in persons who were both infected and vaccinated.