A major study recently published at the Journal of Infectious Diseases showed that natural immunity, or postinfection immunity, was shown to provide 76 percent protection against Covid-19-associated hospitalizations during the Omicron surge, the researchers found. The Moderna or Pfizer vaccines, both using mRNA technology, provided just 39 percent protection for those without a prior infection.
Natural immunity also lasted longer than mRNA vaccination plus boosters, according to the study. During the Omicron surge, natural immunity protection against hospitalization was 74 percent for 150 or more days after infection. A primary vaccine series without prior infection provided just 39 percent protection beyond 149 days after the final shot. Three doses initially provided 81 percent protection but this faded to just 31 percent after 150 or more days following the last shot.