The protection someone gains from having an infection (called natural immunity) varies depending on the disease, and it varies from person to person. Since this virus is new, we don’t know how long natural immunity might last. The level of protection people get from having COVID-19 may vary depending on how mild or severe their illness was, the time since their infection, and their age; and no currently available test can reliably determine if you are protected after a COVID-19 infection. Getting a COVID-19 vaccine gives most people a high level of protection against COVID-19, even in people who have already been sick with COVID-19.

Emerging evidence shows that getting a COVID-19 vaccine after you recover from COVID-19 infection provides added protection to your immune system. One study showed that, for people who already had COVID-19, those who do not get vaccinated after their recovery are more than 2 times as likely to get COVID-19 again than those who get fully vaccinated after their recovery.