Is a 14-day quarantine period optimal for effectively controlling coronavirus disease 2019 (COVID-19)?

Xue Jiang; Yawei Niu; Xiong Li; Lin Li; Wenxiang Cai; Yucan Chen; Bo Liao; Edwin Wang

The incubation period is essential in the control of infectious diseases. To halt a pandemic, a suitable quarantine period should be set by investigating incubation periods. Thus, understanding the characteristics of the incubation period is crucial to design public health efforts. In this cohort, the full range of incubation periods of the Covid-19 cases ranged from 0 to 33 days among 2015 cases. Both male and female adults had their median incubation periods of 7-day, which is 1.8-day longer than those in other reports 3,4 (see discussion). However, a similar result was released in the recent news from the Chinese Medical Association that the median incubation periods were 5-7 days 5 . The median incubation period (9-day) of children were significantly longer than those of adults (t-test P = 0.02). For adults, the incubation periods for the majority (66.5%) of the cases were 1-9 days: most of them (57.6% and 52.0% for males and females, respectively) had 1-5 days incubation. Importantly, we found that the incubation periods of 11.5% (n=233, 123 and 105 were male and female, respectively) of the cases were longer than 14 days, the current WHO-set 14-day quarantine period. These results agree with a recent study which also reported 12.7% (n=13) of the cases whose incubation periods were longer than 14 days 4 . These data suggested that the official 14-day quarantine period only captured 88.5% of the population developing Covid-19.