On January 19, 2022 a CDC study shows that those who have recovered from COVID-19 have more protection against infections from Delta than those who have only been vaccinated.
Four groups of people were analysed:
- unvaccinated with no prior COVID-19 infection,
- vaccinated with no prior infection,
- unvaccinated who recovered from COVID-19, and
- vaccinated who recovered.
Dr Malone summarises: By the first week of October, COVID-19 rates among the vaccinated with no previous infection were 6.2 times lower in [California] and 4.5 times lower in New York than among the unvaccinated with no previous infection.
However, among the unvaccinated with a previous infection, the COVID-19 rate was 29 times lower in California and 14.7 times lower in New York.