Levels of SARS-CoV-2 population exposure are considerably higher than suggested by seroprevalence surveys

• Main Authors: Aguas, R. (Author), Chen, S. (Author), Flegg, J.A (Author), White, L.J (Author)
• Format: Article
• Language: English
• Published: Public Library of Science 2021
• Subjects: article; COVID-19; England; epidemiology; human; Humans; infection fatality ratio; nonhuman; pandemic; Pandemics; physiology; population exposure; SARS-CoV-2; Seroepidemiologic Studies; seroepidemiology; seroprevalence; Severe acute respiratory syndrome coronavirus 2; virology
• Online Access: View Fulltext in Publisher

 Accurate knowledge of prior population exposure has critical ramifications for preparedness plans for future SARS-CoV-2 epidemic waves and vaccine prioritization strategies. Serological studies can be used to estimate levels of past exposure and thus position populations in their epidemic timeline. To circumvent biases introduced by the decay in antibody titers over time, methods for estimating population exposure should account for seroreversion, to reflect that changes in seroprevalence measures over time are the net effect of increases due to recent transmission and decreases due to antibody waning. Here, we present a new method that combines multiple datasets (serology, mortality, and virus positivity ratios) to estimate seroreversion time and infection fatality ratios (IFR) and simultaneously infer population exposure levels. The results indicate that the average time to seroreversion is around six months, IFR is 0.54% to 1.3%, and true exposure may be more than double the current seroprevalence levels reported for several regions of England. © 2021 Chen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.