The new COVID-19 is caused by the virus SARS-CoV-2. WHO is coordinating an effort to understand the potential for persistence of SARS-CoV-2 on foods traded internationally as well as the potential role of food in the transmission of the virus. The most likely ecological reservoirs for SARS-CoV-2 are bats, but it is believed that the virus jumped the species barrier to humans from another intermediate animal host. This intermediate animal host could be a domestic food animal, a wild animal, or a domesticated wild animal which has not yet been identified.

A commentary from the WHO reports on the scientific effort to step up to the challenge. On Feb 10–12, 2020, WHO brought almost 400 scientists together for a research and innovation forum on the new coronavirus. Urgent priorities and work plans were identified by the scientists.

WHO is working with an international network of statisticians and mathematical modelers to estimate key epidemiologic parameters of COVID-19, such as the incubation period (the time between infection and symptom onset), case fatality ratio (CFR, the proportion of cases that die), and the serial interval (the time between symptom onset of a primary and secondary case). Preliminary estimates of median incubation period are 5-6 days (ranging from 0-14 days) and estimates for the serial interval range from 4.4 to 7.5 days.

Initial efforts to understand the behavior of the COVID-19 virus by researchers in Singapore suggest it is different from Severe Acute Respiratory Syndrome (SARS) and has more similarities with H1N1. Like influenza, COVID-19 is infectious when symptoms are mild, the researchers found. Because of this transmission mechanism, COVID-19, like influenza, can spread quite quickly, as people with mild symptoms may let their guard down.