Does Prior Infection Convey More Immunity Than a COVID Vaccine?
A CDC study suggesting as much was pre-omicron and didn’t account for boosters.
Recent viral social media posts from popular right-wing figures and websites have suggested that a recent Centers for Disease Control and Prevention study determined previous coronavirus infections offered greater protection against coronavirus than vaccination.
The CDC published a study on January 19, 2022, which examined COVID-19 cases and hospitalizations in California and New York from May to November 2021. It found that unvaccinated individuals with no previous COVID infection were at highest risk of catching coronavirus, and that while receiving the vaccine initially offered greater protection than having previously been infected by coronavirus, when the Delta variant became the predominant variant “persons who survived a previous infection had lower case rates than persons who were vaccinated alone.”
Contrary to what some of the posts suggest, however, the study does not contradict CDC guidance that vaccinations offered greater protection against the virus: It was only once the Delta variant became the most common strain in the United States that those with a previous COVID infection saw greater protection than the vaccinated. Past strains of COVID saw lower rates of infection among the vaccinated population than the previously infected population. The CDC has also cautioned against applying the findings of this study to the current Omicron variant, which scientists are still researching: It’s not yet clear how natural immunity and vaccine-induced immunity compare. Kristen Nordlund, a CDC public affairs officer, told The Dispatch Fact Check that “those findings only applied to the time of Delta.”
A statement from the CDC notes that the study was also conducted before booster shots became widespread “and does not reflect the immunologic benefit of additional vaccine doses.” Comparing Delta immunity to Omicron immunity “would be like comparing apples and oranges,” a CDC epidemiologist told the Wall Street Journal.
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