What is The Incubation Period of the Coronavirus Disease?

A novel human coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was identified in December 2019. There is limited support for many of its key epidemiologic features, including the incubation period for clinical disease (coronavirus disease 2019 [COVID -19]), which has important implications for surveillance and control activities.

COVID-19 Incubation Period
The incubation period (time from exposure to the development of symptoms) of the virus is estimated to be between 2 and 14 days based on the following sources:

The World Health Organization (WHO) reported an incubation period for COVID-19 between 2 and 10 days. [1]
China ’s National Health Commission (NHC) had initially estimated an incubation period from 10 to 14 days [2].
The United States' CDC estimates the incubation period for COVID-19 to be between 2 and 14 days [3].
DXY.cn, a leading Chinese online community for physicians and health care professionals, is reporting an incubation period of "3 to 7 days, up to 14 days".
The estimated range will be most likely narrowed down as more data becomes available.

This work provides additional evidence for a median incubation period for COVID-19 of approximately 5 days, similar to SARS. Our results support current proposals for the length of quarantine or active monitoring of persons potentially exposed to SARS-CoV-2, although longer monitoring periods might be justified in extreme cases.

 Incubation period is related to the number of viruses and the physique of the infected

The length of the incubation period is related to the amount of virus that initially entered the infected person and the physique of the infected person. Generally, the larger the amount of virus initially entered, the faster the onset and the relatively shorter incubation period. The physical problems are more complicated and cannot be generalized. For example, some people have too strong immunity. When the virus enters the body, the immune molecules respond quickly and excessively attack the host cells infected by the virus, which causes a hypersensitivity reaction, resulting in Lung cells are killed by autoimmunity, which can cause severe symptoms such as pneumonia, and may be infected with other microorganisms.

In this regard, another industry expert said that the length of the incubation period is related to the patient's physical fitness. Some people are well tolerated, while some people are more sensitive, and they can clearly feel it when they are slightly uncomfortable. This subjective thing is difficult To evaluate. Moreover, the virus enters the human body and does not show external symptoms. Whether it belongs to a latent period or an asymptomatic infection is difficult to distinguish at present, and further research is needed.

However, it should be noted that during the incubation period, the virus enters the body without causing a reaction from the immune system, and there are no symptoms, but it cannot be ignored, because there are viruses in the body, it is infectious.