Severity of SARS-CoV-2 reinfections in second wave determines likelihood of mild endemicity

View ORCID ProfileJennie S Lavine,  View ORCID ProfileOttar N Bjornstad,  View ORCID ProfileDaniel Coombs,  View ORCID ProfileRustom Antia

doi: https://doi.org/10.1101/2021.07.21.21260944

This article is a preprint and has not been certified by peer review [what does this mean?]. It reports new medical research that has yet to be evaluated and so should not be used to guide clinical practice.

PDF: https://www.medrxiv.org/content/10.1101/2021.07.21.21260944v1.full.pdf

Abstract

Immunity to SARS-CoV-2 is building up globally, but will this be sufficient to prevent future COVID-19 epidemics in the face of variants and waning immunity? Manaus, Brazil offers a concerning glimpse of what may come: six months after the majority of the city's population experienced primary infection, a second wave with a new strain resulted in more deaths than the first wave. Current hypotheses for this surge rely on prior immunity waning due to time and antigenic distance. Here we show this hypothesis predicts a severe endemic state. We propose an alternative hypothesis in which individuals infected in the first wave lose protection against transmission but retain immunity against severe disease and show this hypothesis is equally compatible with existing data. In this scenario, the increased number of deaths is due to an increased infection fatality ratio (IFR) for primary infections with the new variant. This alternative predicts a mild endemic state will be reached within decades. Collecting data on the severity of reinfections and infections post-vaccination as a function of time and antigenic distance from the original exposure is crucial for optimizing control strategies.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

This work was funded by NIH grants U01 AI150747, U01 HL139483 and U01 AI144616

https://www.medrxiv.org/content/10.1101/2021.07.21.21260944v1