There is still reason to believe the growing coronavirus outbreak in China can be contained, a top World Health Organization official said Saturday, pointing to some evidence that the disease may not be spreading as rapidly as is feared. He also downplayed reports that people infected with the virus may be contagious before they show symptoms — a feature that, if true, would make it much harder to control.
“Until [containment] is impossible, we should keep trying,” Dr. Mike Ryan, head of the WHO’s Emergencies Program, said in an interview with STAT. The WHO declared the outbreak a global health emergency on Thursday.
The gargantuan efforts China is making to try to halt the spread of the virus is buying the rest of the world “precious lead time” to prepare for the possibility they might have to cope with it as well, he said: “We need to thank China for that opportunity.”
“That is not to say that the disease won’t get ahead of the Chinese authorities completely or get ahead of the other countries that are containing it,” Ryan said. “But there’s enough evidence to suggest that this virus can still be contained.”
For instance, data from some studies in China looking at how much transmission occurs when the virus gets introduced into a household suggests the secondary attack rate — the number of people the first case infects — isn’t that high. “But that’s obviously a few studies across a very large event,” Ryan cautioned.
There haven’t been many reports of health worker infections, a feature that fueled the earlier outbreaks of SARS and MERS, coronaviruses that are related to this new pathogen, provisionally called 2019-nCoV. Likewise, there has not been a lot of spread from cases discovered in other countries in tourists from China or people returning from China.
Still, numbers of cases are growing in big leaps — China reported 2,102 new cases and 46 additional deaths on Saturday. And those numbers might be higher still but for the fact that China has a backlog of tests to be processed. Ryan said the problem isn’t testing reagents — the country has indicated it has adequate supplies — but the sheer number of tests that need to be run.
“So there are clear indications obviously that the disease numbers are growing. But there is also some contradictory evidence as well that doesn’t completely align with the kinds of R0s that are being estimated,” Ryan said.
R0 — pronounced R-naught — is the reproductive number of a disease, the number of people, on average, each infected person goes on to infect. Most studies so far have estimated the R0 in this outbreak to be between 2 and 2.5, which is higher than seasonal flu — about 1.3 — but lower than SARS, which had an R0 of between 2 and 5.
Ryan would not say what circumstances would lead the WHO to declare this event a pandemic — an outbreak that might be expected to spread around the globe. That kind of discussion, he said, would be a distraction.
“If that becomes the discussion, then we’re all going to lose focus,” Ryan insisted. “We have to remain laser-focused on containment and slowing down the spread of disease.”
As of Saturday, he said, the world has seen nearly 12,000 confirmed cases, all but 133 of them in China. Nearly two dozen countries outside of China have diagnosed cases. The United States has reported eight cases, one of which contracted the virus in this country from a relative who had traveled to China. The latest U.S. case, confirmed on Saturday, is a University of Massachusetts Boston student in his 20s who returned from a visit to China on Tuesday.
The Trump administration declared the outbreak a public health emergency on Friday, saying it would temporarily bar entry to Chinese nationals who had been in China in the past 14 days and would quarantine Americans returning from China. On Thursday, the State Department told Americans not to travel to China.
There have been a total of 259 deaths reported so far, all in China. “Almost all of the mortality is in the over 40s,” Ryan said “and a strong preponderance of males.” About a third of the cases have pre-existing health problems.
One of the concerns about this outbreak has been reports that people may be able to transmit the virus before they develop symptoms — which, if true, would make containment tools like quarantine less effective than they were during the 2003 SARS outbreak.
A report published Thursday in the New England Journal of Medicine pointed to this type of transmission, sometimes called asymptomatic spread, in a cluster of cases in Germany.
But Ryan said the data the WHO are seeing suggests some people who have been publicly labeled “asymptomatic” were actually already experiencing some symptoms.
“We still believe, looking at the data, that the force of infection here, the major driver, is people who are symptomatic, unwell, and transmitting to others along the human-to-human route,” he said. “That is the pressure wave.”
Ryan admitted he was surprised by the speed with which the outbreak has taken off. China alerted the WHO to the fact that it believed a new virus was causing pneumonia in the central Chinese city of Wuhan on Dec. 31. On Jan. 7 it announced it had isolated a new virus.
The total number of confirmed cases in this outbreak — just a month old — has already surpassed the SARS outbreak, which played out over a period of at least eight months in 2002-2003.
“For me it’s been unusual to see a new disease emerge and, on the face of it, move so quickly,” he said. If the scientists studying the genetic sequences of the viruses are right and the outbreak began sometime in late November or early December, “then this is a very rapid emergence and very rapid infection of a lot of people.”