The specter of Manaus: the risks of a rapid return to pre-pandemic conditions after COVID-19 vaccine rollout

Van Egeren, D.; Stoddard, M.; Novokhodko, A.; Rogers, M.; Joseph-McCarthy, D.; Zetter, B.; Chakravarty, A.

The development and deployment of several SARS-CoV-2 vaccines in a little over a year is an unprecedented achievement of modern medicine. The high levels of efficacy against transmission for some of these vaccines makes it feasible to use them to suppress SARS-CoV-2 altogether in regions with high vaccine acceptance. However, viral variants with reduced susceptibility to vaccinal and natural immunity threaten the utility of vaccines, particularly in scenarios where a return to pre-pandemic conditions occurs before the suppression of SARS- CoV-2 transmission. In this work we model the situation in the United States at present, to demonstrate how the P.1 variant of SARS-CoV-2 can cause a rebound wave of COVID-19 in a matter of months, similar to what happened in Manaus at the beginning of this year. A high burden of morbidity (and likely mortality) remains possible, even if the vaccine is partially effective against new variants and widely accepted. Our modeling suggests that variants that are already present within the population may be capable of quickly defeating the vaccines as a public health intervention, a fatal flaw in strategies that emphasize rapid reopening before achieving control of SARS-CoV-2.