Experts are zeroing in on these and other questions, but clear answers are not yet at hand.
– The Toll So Far –
No deaths have been attributed to the virus outside China.
The 2002/03 SARS outbreak (Severe Acute Respiratory Syndrome) started in Guangdong Province and killed 774 people out of a total 8,096 infected. The 2012 MERS outbreak (Middle East respiratory syndrome) killed 858 people out of the 2,494 infected.
The coronavirus “is less deadly than SARS or MERS, but it is more contagious,” Buzyn said in a press conference Tuesday.
The seasonal flu, by comparison, kills 290,000 to 650,000 people per year, according to the World Health Organization (WHO). In the United States, the mortality rate among people infected with influenza is about 0.13 percent, the Centers for Disease Control has calculated.
– How Contagious ? –
Estimates of how easily coronavirus spreads range from a “base reproduction rate” of 1.4 to 3.8 people infected by a single patient, according to David Fisman, a professor at the University of Toronto.
Chinese scientists, however, have said that one patient, on average, will have spread the virus to 5.5 other people.
“If that proves to be accurate, it would in part explain the surprisingly swift growth of cases in Hubei and beyond, and suggests that China is in for a very rough ride,” said Stephen Morrison from the Center for Strategic & International Studies in Washington.
But the increase in reported cases could also come from “an improved detection capacity in hospitals,” suggest Buzyn.
Scientists at Britain’s Imperial College, meanwhile, estimate that each coronavirus patient infects on average 2.6 others — making it roughly as infectious as annual influenza outbreaks.
– When Is It Contagious? –
This crucial question remains unanswered.
This remains a working hypothesis, and has yet to be confirmed, some experts said.
“In my view it is premature to conclude, on the basis of the evidence currently available, that the new virus can be transmitted before symptoms appear,” said Mark Woolhouse, professor of Infectious Disease Epidemiology, at the University of Edinburgh.
“In the absence of any treatment or vaccine our main hope of controlling the epidemic is the rapid identification of cases and the immediate prevention of onward transmission through patient isolation,” he added.
– Person-to-Person Transmission –
The virus is thought to have originated from a wild animals, probably bats, but is now spreading from person to person.
“If export occurs to countries in Africa and elsewhere where there are limited health security capacities, grave secondary outbreaks could emerge outside of China,” Morrison added.
– What Are the Symptoms? –
All patients had pneumonia, most had a fever, three-quarters of them were coughing and more than half had trouble breathing.
There are, however, some “important differences,” said lead author Bin Lao.
– Incubation Period –
– Avoiding Infection –
Health authorities and scientists say the standard precautions against viral illnesses are applicable: wash your hands frequently, cover up your coughs, try not to touch your face.
Anyone who does come down with the virus should be placed in isolation.
“Considering that substantial numbers of patients with SARS and MERS were infected in health-care settings”, precautions need to be taken to prevent that happening again, the Chinese team warned in The Lancet.