COVID-19: Way Forward With Serosurveillance Without Overemphasizing Neutralizing Antibodies

Serosurveillance of coronavirus disease 2019 (COVID-19) is lagging due to concerns regarding testing performance and interpretation of what represents protective immunity. The scientific community has pointed out concerns related to suboptimal performance of certain tests, although a selection of tests with sensitivity and specificity of >99% is available. Neutralizing antibodies represent a generally accepted surrogate marker of immunological protection against viral infections. In COVID-19, we argue that focusing only on neutralizing antibodies may not be necessary and that evidence of spontaneous clearance of COVID-19 may be a reliable surrogate marker of individuals' immune competency toward future reinfections (regardless of its mechanism) for a period of time. Furthermore, current polymerase chain reaction testing lacks the ability to determine the duration of transmissibility, thus alternatives for direct testing of replicating virus are needed. Broadly applied viable virus testing together with serosurveillance will help reopen the economy with more precision and speed, and help guide isolation, quarantine, and cohorting protocols in conglomerate settings such as correctional facilities, nursing facilities, schools, and long-distance travel.