The brief looks at peer-reviewed and preprint data, as well as data that is unpublished by the CDC to compare infection-induced immunity to vaccine-induced immunity.
The agency said that available evidence shows that those who are fully vaccinated and those who have previously had COVID-19 each have “a low risk of subsequent infection for at least six months.”
While there is a “wide range of antibody titers” in response to previous infection, “completion of a primary vaccine series, especially with mRNA vaccines, typically leads to a more consistent and higher-titer initial antibody response,” the agency said in Friday’s brief.
The CDC has urged everyone, regardless of whether they have been infected, to be vaccinated because it was unclear how long natural immunity lasts. But some have argued that people who recovered from COVID-19 have less need to get vaccinated.
A separate study released from the CDC on Friday, which was based on over 7,000 people across nine states and 187 hospitals, found that vaccination better protects against hospitalization than a previous infection.
In its brief, the CDC noted that there was insufficient data to extend the findings related to infection-induced immunity to persons who had very mild or symptomatic infection, or to children who were infected.
Both types of immunity provided high levels of protection, but not complete.
“Substantial immunologic evidence and a growing body of epidemiologic evidence indicate that vaccination after infection significantly enhances protection and further reduces risk of reinfection, which lays the foundation for CDC recommendations,” the agency said.