WHO says coronavirus has not meaningfully mutated to a more lethal or contagious form

Health, Fitness & Food

Executive Director of the World Health Organization’s (WHO) emergencies program Mike Ryan speaks at a news conference on the novel coronavirus (2019-nCoV) in Geneva, Switzerland February 6, 2020.

Denis Balibouse | Reuters

The coronavirus has not mutated in any way that would meaningfully change how quickly it spreads or how severely it can harm humans, World Health Organization officials said Wednesday. 

The WHO and its network of scientists and virologists continue to track the genetic sequence of the virus in various countries across the world to monitor for mutations, the WHO said. Dr. Maria Van Kerkhove, head of WHO’s emerging diseases and zoonosis unit, said scientists have observed “normal changes” in the virus, which were expected.

“All viruses evolve,” Dr. Mike Ryan, executive director of the WHO’s emergencies program, said at a news briefing from the United Nations agency’s Geneva headquarters. “They can evolve in one direction. They can evolve in the other direction.”

“To date, to my knowledge, we haven’t seen any particular signal in the virus’ behavior or in its sequence that would lead us to believe the virus is changing in its nature, has changed in its transmission dynamics, or changed in its lethality,” he added.

RNA viruses like the coronavirus mutate more quickly than some other viruses, Ryan said, because unlike human DNA, RNA viruses do not have “natural error checking,” meaning that the code of the virus cannot correct itself. That gives RNA viruses some advantages as well as disadvantages, he said.

“The disadvantage is they make many mistakes and many of the viruses don’t thrive or survive,” he told reporters. “Very occasionally, a mutation can lead to a virus becoming more effective in transmission or more virulent, or less effective.”

He added, however, that generally speaking, viruses “evolve to live with humans,” meaning they become less severe so the host can survive and allow the virus to spread more.

“It’s not in the virus’ interest to do too much damage to the host,” he said. “It wants to survive.” 

For the time being, though, the virus is “relatively stable,” Van Kerkhove said. She added that the changes observed in the virus are “expected” and that it is not “mutating in a way that makes the virus more transmissible or more severe.”

That doesn’t mean the virus won’t become more dangerous with time, Van Kerkhove said, adding that it won’t necessarily be due to a mutation. She said that if people or governments become complacent about responding to the virus, it will become more dangerous.

“This is far from over,” she said. ”These public health and social measures may need to be introduced again and that may frustrate people, which is completely understandable. And that in a sense could make the virus more dangerous because people become complacent.”

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