After the World Health Organization on Monday called asymptomatic transmission of coronavirus “very rare,” the WHO had to clarify their position on Tuesday.
Maria Van Kerkhove, head of the WHO’s emerging disease and zoonosis unit, was responding to a journalist’s question when she made the statement that asymptomatic transmission was very rare, but called her words a “misunderstanding.”
“I wasn’t stating a policy of WHO or anything like that,” she said. “We do know that some people who are asymptomatic, or some people who do not have symptoms, can transmit the virus on.”
It was not the “intent of WHO to say there is a new or different policy,” added Mike Ryan, head of emergency programs for WHO. “There is still too much unknown about this virus and still too much unknown about its transmission dynamics.”
No one, including the WHO, knows for sure how frequently asymptomatic transmission occurs, and it is an open question how much it drives the spread. The WHO notes that some countries have not found many cases of asymptomatic spread, while others have found 41% due to asymptomatic transmission.
It is also confusing what it means to be asymptomatic. Some never have symptoms while being infected, and others show symptoms later on after becoming infected, and would be considered “pre-symptomatic.”
“It’s a mess. I don’t know why they would say asymptomatic transmission is very rare when the truth is we simply don’t know how frequent it is,” said Eric Topol, a professor of molecular medicine at Scripps Research. “And it doesn’t change the facts we do know, which is that this virus is very transmissible and is very hard to combat.”
This confusion shows how little is known about the novel virus, making it difficult to communicate discrepancies, and yet the public has an intense desire to know the data to uphold a stance on the pandemic response.
Many scientists view the WHO’s response as irresponsible because it can erode the public’s confidence and willingness to take precautions.
Still, the CDC says it remains essential that people wear masks to prevent the spread of the virus.
“All of the best evidence suggests that people without symptoms can and do readily spread SARS-CoV-2, the virus that causes Covid-19,” the Harvard Global Health Institute said in a statement Tuesday. “In fact, some evidence suggests that people may be most infectious in the days before they become symptomatic.”
Yet most experts admit that all studies on the subject are “imperfect in many ways,” and that it’s important to say that there is much we do not know about the novel virus. Asymptomatic shed is one aspect scientists are still unsure of.
The details of this article can be found at Washington Post, where paywalls are waived for information on the coronavirus.