PT  - JOURNAL ARTICLE
AU  - Andrew William Byrne
AU  - David McEvoy
AU  - Aine B Collins
AU  - Kevin Hunt
AU  - Miriam Casey
AU  - Ann Barber
AU  - Francis Butler
AU  - John Griffin
AU  - Elizabeth A Lane
AU  - Conor McAloon
AU  - Kirsty O'Brien
AU  - Patrick Wall
AU  - Kieran A Walsh
AU  - Simon J More
TI  - Inferred duration of infectious period of SARS-CoV-2: rapid scoping review and analysis of available evidence for asymptomatic and symptomatic COVID-19 cases
AID  - 10.1136/bmjopen-2020-039856
DP  - 2020 Aug 01
TA  - BMJ Open
PG  - e039856
VI  - 10
IP  - 8
4099  - http://bmjopen.bmj.com/content/10/8/e039856.short
4100  - http://bmjopen.bmj.com/content/10/8/e039856.full
SO  - BMJ Open2020 Aug 01; 10
AB  - Objectives Our objective was to review the literature on the inferred duration of the infectious period of COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, and provide an overview of the variation depending on the methodological approach.Design Rapid scoping review. Literature review with fixed search terms, up to 1 April 2020. Central tendency and variation of the parameter estimates for infectious period in (A) asymptomatic and (B) symptomatic cases from (1) virological studies (repeated testing), (2) tracing studies and (3) modelling studies were gathered. Narrative review of viral dynamics.Information sources Search strategies developed and the following searched: PubMed, Google Scholar, MedRxiv and BioRxiv. Additionally, the Health Information Quality Authority (Ireland) viral load synthesis was used, which screened literature from PubMed, Embase, ScienceDirect, NHS evidence, Cochrane, medRxiv and bioRxiv, and HRB open databases.Results There was substantial variation in the estimates, and how infectious period was inferred. One study provided approximate median infectious period for asymptomatic cases of 6.5–9.5 days. Median presymptomatic infectious period across studies varied over <1–4 days. Estimated mean time from symptom onset to two negative RT-PCR tests was 13.4 days (95% CI 10.9 to 15.8) but was shorter when studies included children or less severe cases. Estimated mean duration from symptom onset to hospital discharge or death (potential maximal infectious period) was 18.1 days (95% CI 15.1 to 21.0); time to discharge was on average 4 days shorter than time to death. Viral dynamic data and model infectious parameters were often shorter than repeated diagnostic data.Conclusions There are limitations of inferring infectiousness from repeated diagnosis, viral loads and viral replication data alone and also potential patient recall bias relevant to estimating exposure and symptom onset times. Despite this, available data provide a preliminary evidence base to inform models of central tendency for key parameters and variation for exploring parameter space and sensitivity analysis.