Letter to the Editor: Coronavirus Disease 2019 (COVID-19), Infectivity, and the Incubation Period.

Dear Editor,

We read with great interest the recent publication entitled “A Chinese case of coronavirus disease 2019 (COVID-19) did not show infectivity during the incubation period: based on an epidemiological survey” [1]. Bae concluded that “the epidemiological findings support the claim that the COVID-19 virus does not have infectivity during the incubation period [1].” In fact, a pathogen should not have infectivity during the incubation period or development of disease. However, the exact incubation period of COVID-19 is still unknown. In a recent report by Linton et al. [2], the incubation range was estimated as between 2 days and 14 days with 95% confidence. Exceptional cases might occur with an unusually short or long incubation period. Nevertheless, the reliability of history-taking should also be addressed. How the author was able to confirm the reliability of the patient’s self-reported history is an interesting issue for further discussion. In our country, Thailand, it is not uncommon for patients to disguise their clinical history, which can cause delays in the diagnosis of COVID-19 and exacerbate the local transmission of the disease.