The new coronavirus that has killed 42 people since September, most of them in Saudi Arabia, is less transmissible than the related SARS virus and probably won’t touch off a pandemic, a study found.
Researchers from France’s Pasteur Institute analyzed clusters of infections involving 55 of the first 64 cases of Middle East respiratory syndrome coronavirus, or MERS-CoV, and calculated that each case resulted in an average of 0.69 subsequent infections, compared with 0.8 for the SARS virus. The findings were published in The Lancet today.
The previously unknown virus has sickened 79 people, according to the World Health Organization, which said today it will convene a committee of experts next week to decide whether the new virus poses a public health emergency of international concern.
“Given the overall pattern where we’re seeing steady cases, and where we don’t know what the future brings, what we just want to make sure is that we can move as quickly as possible if we need to,” Keiji Fukuda, the WHO’s assistant director-general for health security and environment, said at a briefing in Geneva today. “We’re not in the midst of any acute event right now.”
The committee, which will meet via teleconference July 9 and again on July 11 if necessary, will involve external experts who will assess information on the outbreak and advise the Geneva-based WHO on whether it needs to make any further recommendations about the risk posed by the virus, Fukuda said.
It’s only the second time the committee has been convened, after the H1N1 swine flu pandemic of 2009, Fukuda said. The WHO will announce the names of the committee members on July 8, he said.
Health officials still don’t know where the virus came from or how it’s being transmitted, Fukuda said. Identifying the source should be a “high priority” that focuses on animals known to host coronaviruses, including bats, birds, mice, dogs, pigs and cattle, researchers led by Arnaud Fontanet, a professor of epidemiology, wrote in today’s study.
“MERS-CoV has not spread as rapidly or as widely as SARS did,” Fontanet said in an e-mailed statement. “SARS’s adaption to humans took just several months, whereas MERS-CoV has already been circulating more than a year in human populations without mutating into a pandemic form.”
Cases in the U.K., France, Germany and Italy have raised concern it may develop into a global pandemic like SARS, which killed 774 people a decade ago and caused almost $40 billion in economic losses.
“The most important missing data is where the virus is coming from, as once that is known even these few cases should be largely avoidable,” Ian Jones, a professor of virology at the University of Reading, said in a statement.
The virus may be more transmissible than estimated if there are many more undetected mild cases, the researchers cautioned. One patient hospitalized in the U.K. died June 28 from severe respiratory illness, Guy’s and St Thomas’s NHS Foundation Trust said in a statement yesterday.
Saudi Arabia hasn’t reported a new case since June 23, after finding 26 cases in the previous month. Thousands of other people who have had contact with those infected have tested negative for the virus, suggesting it’s not easily transmissible, the WHO has said.
Still, MERS-CoV does spread easily in hospitals, according to a study in the New England Journal of Medicine last month. One patient at a hospital in Saudi Arabia’s eastern al-Ahsa region contaminated six others who were receiving dialysis in the same ward at the same time, the study found.
“The authors have done their best to predict how MERS will spread based on the few cases that we know about, and found that the virus appears to be slowly dying out,” Benjamin Neuman, from the University of Reading’s Microbiology Research Group, said in a statement. “But other work has shown that the virus is changing, and that change makes it difficult to predict the future.”