Israeli Maccabi study reports prior infection outperformed two Pfizer doses against Delta
Researchers at Maccabi Healthcare Services, Israel's second-largest health fund, posted a non-peer-reviewed preprint comparing reinfections among previously infected, unvaccinated people with breakthrough infections among fully vaccinated, never-infected people during Israel's Delta wave (follow-up June 1–August 14, 2021). Among people infected or vaccinated in January–February 2021, it reported a 13.06-fold higher risk of breakthrough infection in the vaccinated group than of reinfection in the previously infected group, while also finding that previously infected people who received a single vaccine dose gained additional protection. The largest study of its kind at the time, it drew wide attention along with immediate cautions about its observational design, small outcome counts, and lack of peer review; similar Israeli analyses (including a December 2021 Israel Ministry of Health analysis of waning natural and hybrid immunity) followed.
Primary quotes
“natural immunity confers longer lasting and stronger protection against infection, symptomatic disease and hospitalization caused by the Delta variant”
Gazit et al., medRxiv preprint (authors' conclusion)
“What we don't want people to say is: 'All right, I should go out and get infected, I should have an infection party.'”
Immunologist Michel Nussenzweig, quoted in Science via FactCheck.org
Flags / open questions
- •Non-peer-reviewed preprint at time of reporting (observational design, small outcome counts)
Linked sources
Related contentions
The timeline of what officials said and when is well documented; the dispute is over interpretation — whether the gap between emerging evidence and official acknowledgment reflected scientific caution or messaging discipline. No official review has adjudicated the claim, and the question remains contested.