It’s hard to know yet. But the fatality rate is
probably less than 3 percent, much less than SARS.
This is one of the most important factors in how damaging the outbreak will be, and one of the least understood.
It’s tough to assess the lethality of a new virus. The worst cases are usually detected first, which can skew our understanding of how likely patients are to die. About a third of the first 41 patients reported in Wuhan had to be treated in an I.C.U., many with symptoms of fever, severe cough, shortness of breath and pneumonia. But people with mild cases may never visit a doctor. So there may be more cases than we know, and the death rate may be lower than we initially thought.
At the same time, deaths from the virus may be underreported. The Chinese cities at the center of the outbreak face a shortage of testing kits and hospital beds, and many sick people have not been able to see a doctor.
“There’s still a lot of uncertainty about what this virus is like and what it is doing,” said Dr. Allison McGeer, an infectious disease specialist at Mount Sinai Hospital in Toronto, who was at the frontlines of the Canadian response to SARS.
Early indications suggest the fatality rate for this virus is considerably less than another coronavirus, MERS, which kills about one in three people who become infected, and SARS, which kills about one in 10. All of the diseases appear to latch on to proteins on the surface of lung cells, but MERS and SARS seem to be more destructive to lung tissue. As of Jan. 31, fewer than one in 40 of the people with confirmed infections had died. Many of those who died were older men with underlying health problems.
