key: cord-311979-l1iw6449
authors: Cimolai, Nevio
title: More data are required for incubation period, infectivity, and quarantine duration for COVID-19
date: 2020-04-27
journal: Travel Med Infect Dis
DOI: 10.1016/j.tmaid.2020.101713
sha: 
doc_id: 311979
cord_uid: l1iw6449

nan

in some respiratory, urine, and stool samples for more than fourteen days [2] . For MERS-CoV, nasopharyngeal samples have yielded live virus in some past fourteen days [3] .

Early reports from the Asian COVID-19 experience continue to prompt a need to reconsider if not revise approaches to control. Some have proposed possible transmission during the incubation period [4] . The suggestion that the incubation period can be extended beyond fourteen days is receiving support [5] . Although it is more common for the incubation period to be less than one week, 97 to 99% confidence intervals for the tail-end of excretion are more than double the latter timing. If the majority of patients become ill in less than two weeks, the finding of outliers beyond the latter may not be common in a small affected population. To the contrary, a very large population being affected is very likely to have such outliers which could complicate the pattern of spread.

Some patients shed the virus in a relatively asymptomatic state [6] . The latter will again have the potential to complicate control measures. Furthermore, the concept that patients only excrete virus when they become symptomatic is not in keeping with most known viral respiratory infections otherwise.

The existing data therefore beckon reconsideration of several important parameters. For the definition of the infectious period, an initiation of timing prior to the actual onset of symptoms, if they occur, seems prudent. Likewise, an extension to a safer end limit for excretion past fourteen days could also attract support. Extension to the quarantine period for a patient with a laboratory-confirmed infection or for a definitive close contact should be considered. Greater stringency for the follow-up of casual contacts could also be applicable.

If COVID-19 was largely a mild disease, further stringency in these regards would be unpalatable to many. In these uncertain times, given the crescendo to a global pandemic and given the observed morbidity, some further consideration should be given to these very important epidemiological topics. Most will recognize that an extension to infectious periods or isolation/quarantine times has the potential to significantly complicate resources or unduly stretch capabilities, but error towards greater safety has its merits. In large part, we have relied on China to provide timely epidemiological data, but other countries are now in a position to re-analyze some of these critical issues as

Lagier and colleagues and others have rightfully begun.

Testing the repatriated for SARS-Cov2: should laboratory-based quarantine replace traditional quarantine

Environmental contamination and viral shedding in MERS patients during MERS-CoV outbreak in South Korea

A familial cluster of infection associated with the novel 2019 novel coronavirus indicating possible person-to-person transmission during the incubation period

The incubation period of coronavirus disease

COVID-19) from publicly reported confirmed cases: estimation and application

Unique epidemiological and clinical features of the emerging 2019 novel coronavirus pneumonia (COVID-19) implicate special control measures