WHO tries to clean up ‘asymptomatic’ comments

The World Health Organization backtracked Tuesday from its claim a day earlier that asymptomatic spread of COVID-19 was “very rare,” which had befuddled world leaders and public health officials who shut down economies in part because of the fear that people who don’t feel sick would spread the virus.

Maria Van Kerkhove, WHO’s technical lead on COVID-19, said her Monday comment was based on “two or three studies” that tracked asymptomatic cases, plus their contacts, to see who else was infected. She said some models estimate up to 40% of transmission may be due to asymptomatic people, though cautioned it remains an “open question.”

“I was responding to a question at the press conference. I wasn’t stating a policy of WHO or anything like that. I was just trying to articulate what we know,” Dr. Kerkhove said in a live-streamed Q&A on social media.

Public health experts thanked WHO for clarifying but said they shot themselves in the foot at a pivotal point in the pandemic, as countries emphasize mask wearing and other public health measures as part of reopening plans.

“The WHO has already gotten a lot of bad press recently regarding COVID. I think this was a good person who forgot that she was not at an epidemiological meeting where we could get a little bit prissy about the details, and she just obscured the major public health messaging,” said William Schaffner, an infectious-disease specialist at Vanderbilt University. “They have created some confusion, and the rest of us are trying to unring the bell.”

The walk-back underscored how much of the science around the coronavirus remains elusive six months after the pathogen was discovered in humans in Wuhan, China.

Attempts to understand asymptomatic spread are unfolding as the U.S. and other places try to get back to normal. Governors are lifting stay-at-home orders to reopen businesses and institutions, meaning people who have the virus but don’t realize it will be mingling with others.

Nationwide protests responding to the death of George Floyd, a black man who died after a white officer kneeled on his neck in Minneapolis, consist of massive gatherings of people, raising fears that marchers who feel healthy will spread the virus or bring it back to their communities.

President Trump retweeted photos of the protests Tuesday in declaring he’s ready to resume his trademark campaign rallies as soon as next week, citing “big demand,” even as the U.S. case count nears 2 million and death toll exceeds 111,000.

“Reopen America!” tweeted Rep. Jim Jordan, Ohio Republican, on Tuesday alongside a story about the initial WHO comments, suggesting Monday’s assertion had taken root.

WHO officials said they still believe the majority of known transmission is from people who show symptoms and spread the virus to others through infectious droplets. They do, however, believe people who don’t feel sick “can transmit the virus on.”

“I’m absolutely convinced that that is occurring. The question is how much,” said Mike Ryan, director of WHO’s emergencies program.

Public health experts said Dr. Kerkhove’s “very rare” comment on Monday may have been technically accurate, based on the relevant studies, but that it amounted to a public health-messaging flub.

Mr. Trump already said the U.S. will terminate its relationship with WHO over the agency’s handling of the virus, saying it gave deference to China, and some people doubt the official information they’re getting about the brand-new disease, since guidance keeps changing.

“Communicating preliminary data about key aspects of the coronavirus without much context can have tremendous negative impact on how the public and policymakers respond to the pandemic,” scientists at the Harvard Global Health Institute said in a Tuesday statement. “If new evidence becomes available, WHO should be transparent, make all available data publicly accessible and take the time to thoroughly brief the media and the public on the nature and interpretations of the findings.”

Andy Slavitt, who led federal insurance programs under President Obama, said the WHO made an “innocent but significant mistake” at a time “when we need credible sources.”

“They need to understand that this isn’t a science project, but [that] the world is listening,” he said in an email. Massachusetts Gov. Charlie Baker said he didn’t put much stock in what WHO said Monday because data from his state suggest asymptomatic spread is a big problem.

“Huge numbers, huge percentages of people who tested for the coronavirus antibodies — which means they were infected and shedding virus at some point — said they were never sick. OK?” Mr. Baker, a Republican, said Tuesday.

Also, “there is a lot of anecdotal information about the impact that asymptomatic workers in long-time care facilities had with regard to the spread of coronavirus,” he said.

WHO officials and others say it is important to differentiate between people who are asymptomatic, meaning they never develop signs of their infection, and those who are pre-symptomatic, in which they may test positive for the virus a few days before they show symptoms.

That distinction isn’t always made, which may fuel confusion about the topic.

“Some have some mild disease. They may not quite register that ’I’m sick,’” Dr. Kerkhove said.

Like the asymptomatic camp, the scientific community is trying to figure out the extent to which the pre-symptomatic spread the disease.

“In fact, some evidence suggests that people may be most infectious in the days before they become symptomatic — that is, in the pre-symptomatic phase when they feel well, have no symptoms, but may be shedding substantial amounts of virus,” the Harvard scientists said. “The implications here are considerable: because people without symptoms can and do spread the disease, we need to continue to all wear masks when around others, maintain 6 feet distance, and wash hands regularly.”

WHO recommends that people wear masks if they are in places where there is active transmission of the virus and they cannot put physical distance between themselves and others.