Natural immunity 97% effective against severe COVID-19 after 14 months
The protection against severe illness from so-called natural immunity remains superior to the protection bestowed by COVID-19 vaccines, according to a new study.
People who survived COVID-19 infection and were not vaccinated had sky-high protection against severe or fatal COVID-19, researchers in Qatar found.
“Effectiveness of primary infection against severe, critical, or fatal COVID-19 reinfection was 97.3 percent … irrespective of the variant of primary infection or reinfection, and with no evidence for waning. Similar results were found in sub-group analyses for those ≥50 years of age,” Dr. Laith Abu-Raddad, with Weill Cornell Medicine-Qatar, and colleagues said after studying long-term natural immunity in unvaccinated people.
That percentage is higher than the protection from COVID-19 vaccines, according to other studies and real-world data.
Swedish researchers, for instance, found in May that two doses of a vaccine were just 54 percent effective against the Omicron variant of COVID-19. South African scientists, meanwhile, found the effectiveness of the AstraZeneca and Pfizer vaccines peaked at 88 percent, and quickly dropped to 70 percent or lower.
The Qatar group found natural immunity for over 14 months after a person’s first infection “remains very strong, with no evidence for waning, irrespective of variant.”
Few researchers have studied natural immunity long-term among unvaccinated persons, in part because many of the people have eventually received a COVID-19 vaccine. The vaccines, meanwhile, have waned against both infection and severe illness over time, triggering recommendations for booster doses, with some Americans even getting five doses within 10 months.