That's a really complicated question, because of the effect of variants. Here's some "safe" statements I think we can say.
It
seems like antibody levels are a
good indicator of vaccine efficacy, which means they're probably also predictive of protection against reinfection.
Antibody levels in vaccinated individuals are generally
higher than convalescent and more predictable (see Fig 1A). However, convalescent people have antibodies to both the N protein and the S protein (see Fig 1B). You can see that some convalescent people don't have a strong antibody response to N and/or S, which probably depends on disease severity.
Antibodies generated by vaccines look like they
bind more broadly to potential single-protein mutations on the spike than convalescent ones, and are more focused on the "business end" (receptor-binding domain) of the spike than convalescent antibodies. This means that we
might expect vaccinated individuals to have better immunity versus some variants than recovered patients.
This is countered by the fact that while the infection-developed antibodies may be less focused on the receptor-binding domain, they are broader since the immune system develops antibodies to the N protein as well. If you read the second paper above, you'll see that not everyone they checked for antibodies who was unvaccinated but previously recovered actually had N-type antibodies. Weird, but small sample size.
Some of the differences in response could be
- the vaccine mRNA spike may be presented to the body in a slightly different shape
- the way its presented to the body immune system may be different
- natural infection only generally presents in the respiratory system vs in the muscle for vaccine
So long story short.
- If you could somehow freeze mutations, it's likely that the vaccines are better than infection versus that specific virus
- Depending on the mutation, vaccine-induced antibodies might give better protection against a variant because of broader binding to the spike receptor-binding domain
- Depending on the mutation, infection-induced antibodies might give better protection against a variant because there's more parts of the virus to respond to
Long story shorter - we don't really know for sure yet, because forecasting the future is hard and the immune system is complicated. We don't even know for sure whether reinfection from the other human corona viruses is because immunity wanes or because the viruses mutate, or both.
