Determining the period of communicability of SARS-CoV-2: A rapid review of the literature

Park, M.; Pawliuk, C.; Nguyen, T.; Griffitt, A.; Dix-Cooper, L.; Fourik, N.; Dawes, M.

Introduction: How long individuals may transmit virus after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unclear. Understanding the communicability period of SARS-CoV-2 is important to inform the period of isolation required to prevent nosocomial and community spread. The objective of this study was to identify the reported communicable period of SARS-CoV-2, based on a rapid review of existing literature. Methods: Studies reporting empirical data on the period of communicability of SARS-CoV-2 through investigations of duration of communicability based on in-person contact ('contact transmission'), isolation and culture of virus ('viral isolation'), and viral shedding by detection of nucleic acids by RT-PCR ('viral shedding') were identified through searches of peer-reviewed and pre-print health sciences literature databases (Ovid MEDLINE, Embase, Google Scholar, medRxiv and arXiv) and the grey literature. Articles were screened for relevance, then data were extracted, analyzed, and synthesized. Results: Out of the 165 studies included for qualitative analysis, one study investigated contact transmission, three investigated viral isolation, 144 investigated viral shedding, and 17 studies focused on both viral shedding and viral isolation. The median length of time until viral clearance across all viral isolation studies was nine days; however, the maximum identified duration was 32 days. Studies with data on both viral isolation and viral shedding showed a prolonged maximum time until viral clearance for viral shedding (9 days vs 24 days). Discussion: Findings from this review support a minimum 10-day period of isolation; however, additional observation should be considered for individuals being released into high-risk settings.