A new report released on Wednesday by the Centers for Disease Control and Prevention (CDC) revealed that unvaccinated people who recovered from COVID-19 were better protected than those who were vaccinated and not previously infected during the recent delta surge.

The researchers evaluated the data from 1.1 million Covid-19 cases among adults in California and New York (which account for 18% of the U.S. population) from May 30 to Nov. 20, 2021.

The study was divided into four groups of adults aged 18 above: 1) unvaccinated with no previous laboratory-confirmed COVID-19 diagnosis, 2) unvaccinated with a previous COVID-19 diagnosis, 3) vaccinated (14 days) with no previous COVID-19 diagnosis, and 4) vaccinated with a previous COVID-19 diagnosis.