A Sep 25 letter from the head of the United Kingdom Department of Health to UK health workers said the incubation period for the new virus is assumed to be 7 days, given what is known about other human coronavirus infections. The letter to UK National Health Service workers was written by Dame Sally C. Davies, chief medical officer.
A then-novel coronavirus sparked the SARS (severe acute respiratory syndrome) outbreak in 2003, which involved more than 8,422 cases globally and killed 916 people, according to the ECDC risk assessment. Aside from the outbreak, human coronaviruses are mainly known for causing colds. Health officials have stressed that the new coronavirus is clearly different from the SARS virus.
Both the Davies letter and the ECDC risk assessment said no suspected cases have been found among contacts of the Qatari patient or elsewhere. "Many of these contacts are already likely to be beyond the incubation period . . . when symptoms would have developed had they been infected," Davies wrote.
The ECDC said that as of yesterday it was not aware of "any increase in the number of patients with acute respiratory infections of unknown cause in intensive care units in Saudi Arabia or Qatar."
The ECDC statement filled in some new details on the 60-year-old Saudi Arabian who died. It said he fell ill on Jun 6, was hospitalized with severe pneumonia on Jun 13, and died on Jun 24.
The fact that the two cases occurred 3 months apart and that time spent in Saudi Arabia is the only known link means that "independent non–human-to-human transmission must be considered" and that an animal source can't be excluded, the ECDC said.