Thread by @SetteLab

Is the protection resulting from natural infection better than the protection resulting from vaccination?

One report from Israel suggests natural infection is superior medrxiv.org/content/10.110…, and UK study and a Kentucky study ndm.ox.ac.uk/files/coronavi…
cdc.gov/mmwr/volumes/7…
appear to reach different conclusions.

For medical records surveys it is difficult to control for under-reporting asymptomatic infections, behavior, and times at which subjects became eligible for vaccination.A strong point of the UK study is that it also involved actual households PCR tests to measure infections.

It is true that natural infection provides substantial protection from reinfection. And it is also true that vaccination provides substantial protection.

Comparing the two; Immune responses induced by natural infection are weak in about 10% of people after 8-months; having been infected does not ensure the presence of good humoral and T cell responses. Responses induced by natural infection are in general of lower magnitude.

However, currently vaccines only induce responses against spike. T cells against non-spike antigens induced by infection might make a substantial difference. And the localized response resulting from infection might more effective than systemic response resulting from vaccination

Comparing protection from infection or vaccination, the question is not “should I get COVID or be vaccinated”? COVID is associated with high disease burden, risk of death and long-lasting health issues (long COVID), in contrast with the excellent safety profile of vaccination.

The question is "should I get vaccinated even if I previously had covid?" People that were infected and then vaccinated develop a powerful immune response, called “hybrid immunity”, which exceeds what is seen with either natural infection or vaccination.

A higher immune response would be expected to overcome decreased capacity of antibodies to neutralize variants. Studies have shown that even a single shot of RNA vaccine is capable of inducing strong responses in previously infected individuals.

Break-trough infections, albeit associated with lower disease severity, can spread infection to unprotected people. Bottom line, vaccination of previously infected individuals provides strong benefit to the individual, and to others as well.