Israeli study: People with natural immunity have more protection than double-dose vaccinated
RESULTS
Confirmed infection rates increased according to time elapsed since the last immunity-conferring
event in all cohorts. For unvaccinated previously infected individuals they increased from 10.5
per 100,000 risk-days for those previously infected 4-6 months ago to 30.2 for those previously
infected over a year ago. For individuals receiving a single dose following prior infection they
increased from 3.7 per 100,000 person days among those vaccinated in the past two months to
11.6 for those vaccinated over 6 months ago. For vaccinated previously uninfected individuals
the rate per 100,000 person days increased from 21.1 for persons vaccinated within the first two
months to 88.9 for those vaccinated more than 6 months ago.
CONCLUSIONS
Protection from reinfection decreases with time since previous infection, but is, nevertheless,
higher than that conferred by vaccination with two doses at a similar time since the last
immunity-conferring event. A single vaccine dose after infection helps to restore protection.
https://www.medrxiv.org/content/10.1101/2021.12.04.21267114v1.full.pdf