| > 15 weeks is rather short. Additionally, it's not really 15 weeks. You're right. It's the lower bound, based on the duration of the experiment. There have now been many, many studies all pointing in the same direction. A small selection: https://www.thelancet.com/journals/lancet/article/PIIS0140-6... Natural infection protects against Covid (incl. Alpha variant). Adjusted incidence rate ratio for covid infection - 0.159 (84% protection) and symptomatic covid - 0.074 - (93% protection) - 7 month follow up https://jamanetwork.com/journals/jamainternalmedicine/fullar... Patients who had 1 PCR positive tests had Hazard ratio 0.06 of further positive PCR - 94% protection - 12 month follow up. https://academic.oup.com/cid/advance-article/doi/10.1093/cid... After 1 positive PCR, Protection against any COVID - 81.8%, symptomatic COVID - 84.5% - 6 month follow up - protection increased over time. https://academic.oup.com/cid/advance-article/doi/10.1093/cid... seropositive patients had 94% reduction in hazard of testing positive - 8 month follow up https://www.nejm.org/doi/full/10.1056/NEJMoa2034545 Adjusted risk ratio of covid infection for antibody positive healthcare workers was 0.11 (89% less likely) - 7 month follow up period. All reinfections were asymptomatic. At this point, claiming that immunity to Covid (even against "the variants") is less than a year is an extraordinary claim. There is no reason, prima facie to presume that the results will be different for vaccines. |
I'm not sure I agree with just assuming protection will last that long as a default. This study does not establish it but it is a good stepping stone to proving that theory.
re: your edits, the tangential bit from this paper about sars-cov-2 positive cases wasn't the main thrust and from the graphs it looks like their neutralizing antibody levels actually are multiple logs below mRNA vaccinated people at the same 15 week point. I'm not sure what all these citations about naturally infected people add to the topic being debated.