Despite what members of the public may have heard earlier this week, on cable news, social media, or in video snippets of a few opaque sentences spoken by a World Health Organization official at a press briefing on Monday, the W.H.O. did not announce, report, or discover that people who are infected with the SARS-CoV-2 virus but have no symptoms hardly ever transmit it to others. (Some headlines left the impression that such people aren’t contagious at all.) They can and do spread the disease, and the W.H.O. knows it. As Michael Ryan, an Irish epidemiologist and a veteran of two Ebola epidemics and the campaign to eradicate polio, who is leading the W.H.O.’s response to COVID-19, said on Tuesday, “It’s clear that both symptomatic and asymptomatic individuals are part of the transmission cycle.” Ryan was speaking at a Facebook Live event that the W.H.O. had hastily convened to offer a “clarification” of remarks that his colleague Maria Van Kerkhove, an American epidemiologist who is the team’s lead technical consultant, had made the day before, in which, out of context, she seemed to say that such transmission was “very rare,” inspiring the startling headlines. There had been a “misunderstanding,” Van Kerkhove said at the event; there was no new statement or policy, whatever the impression. “Maybe we didn’t use the most elegant words,” Ryan said.
That is an understatement. The words were terribly misleading, and epidemiologists were concerned that they might drive people to think that social distancing and masks only make sense for those who clearly have symptoms. On Wednesday, Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, went on “Good Morning America” to say that the idea that asymptomatic people were only rarely contagious is “not correct.” But, in part because the comments came in the midst of the drive to reopen, others seized on them. “Good News! People who catch coronavirus but have no symptoms rarely spread the disease,” Senator Rand Paul tweeted. “Translation: sending kids back to school does not require millions of test kits.” In fact, it does. Although the over-all numbers of new deaths and cases are down in the United States, they are rising or even spiking in certain states, such as Arizona, the Carolinas, Florida, Tennessee, Texas, and some parts of California. And that is even before the full effect of gatherings and protests (and mass arrests) over the past two weeks, if any, can be registered. It is precisely the moment to test aggressively, to head off or blunt a second wave—which actually might keep schools from reopening.
The source of the confusion is an answer that Van Kerkhove gave to a question from Reuters about new findings from Singapore which indicate that a strikingly high number of people with COVID-19 are asymptomatic—perhaps as many as half. (That conclusion came as Singapore increased testing.) Van Kerkhove began with a disquisition on whether people who think they are asymptomatic are really asymptomatic or whether they have very mild symptoms or ones that are “not quote-unquote COVID symptoms.” She also noted that there is a distinction between truly asymptomatic infected people, who never experience any effects, and presymptomatic infected people, who eventually feel something. Then, without quite clarifying which kind of asymptomatic person she was talking about, she brought up some “reports” from unnamed W.H.O. member countries that have engaged in “detailed contact tracing” of asymptomatic people and are “not finding secondary transmission onward”; however, much of that information was unpublished, she said, and thus neither peer-reviewed nor publicly available, and the W.H.O. was “trying to get more information from countries to truly answer this question.” In that very preliminary, narrow context, she said, it “still appears to be rare that an asymptomatic individual transmits onward.” But, as she said in the Facebook event, she did not mean that this applied “globally.” She was talking only about “a small subset of studies”; like Ryan, she noted that asymptomatic people can transmit the disease.
Van Kerkhove was making a useful point about the term “asymptomatic” being applied too broadly; in the midst of a pandemic, though, it needed to be better expressed. The larger damage was done when she combined that observation about terminology with what came across as a general statement about who is contagious. In doing so, she undermined the message that, for example, people should wear masks in public even if they don’t think they are ill. (After all, as she herself acknowledged, they are the people who define themselves as asymptomatic.) This was especially harmful because, as both she and Ryan noted in the Facebook event, studies have shown that an infected person’s “viral load”—the amount of SARS-CoV-2 in their body—seems to be highest around the time that symptoms first appear. This raises the possibility that people who appear to be asymptomatic but are, in fact, presymptomatic may be particularly contagious.
Also, the virus is present in the upper respiratory tract, so it appears that it can spread simply through, as Ryan put it during the event, “singing, speaking loudly, exertion, maybe in a gym . . . shouting in a night club because you can’t hear your friend.” (Coughing and sneezing, of course, are likely to spread virus-bearing droplets farther through the air, which is a reason that symptomatic patients could infect more people; an unanswered question is how much each group drives the pandemic.) Someone might go to a restaurant “feeling O.K.,” but their “viral load could be actually quite high.” (In a key epidemiological study showing how the virus spread from table to table in a restaurant in China, the initial patient didn’t report symptoms until hours after having eaten there.) Ryan emphasized that this was a reason for wearing masks. “There is this period of time when, you know, even a professor of infectious diseases themselves wouldn’t know that I’m getting COVID,” Ryan said. “There is that hours or days in which you’re not that unwell, or you could be becoming unwell, you’re not aware of your status, and it’s because the disease can spread at that moment that the disease is so contagious. That’s why it’s spread around the world in such an uncontained way. It’s because it’s hard to stop this virus.”
But it can be stopped. There was an important, and perhaps promising, observation wrapped in the confusion of Van Kerkhove’s initial comments: if some contact-tracing studies are showing that asymptomatic people in certain places aren’t infecting many others, why aren’t they? Is it because they live in countries where people have been wearing masks, are rigorous about social distancing, or are largely in complete shutdown? Is it because of the speed of the contact tracing itself, or other measures those countries are taking? If it means that there are measures short of lockdown to keep people without symptoms from being major drivers of the pandemic, that could also be very good to know.
An obvious lesson from the episode is that the W.H.O. must communicate better. The Times, in a report on the Facebook event, quoted scientists who worry that the W.H.O. has fallen behind in synthesizing the latest and best research on the disease. An example is its delay in issuing guidance on broad mask-wearing, which it did just last week. When the first outbreaks emerged in China, the W.H.O. was slow even to confirm that the coronavirus could spread from person to person rather than from animals to people. At the Facebook Live event, Van Kerkhove, referring to the enduring uncertainty on many questions about the virus, told viewers that it is still “early days.” Undoubtedly, in terms of humanity’s relationship with the coronavirus, it is. But, with more than four hundred thousand people dead around the world, some hundred and thirteen thousand of them in the United States, it’s beginning to feel a bit late to be making such mistakes in the public-health messaging.
It can be painful for the W.H.O.’s supporters to make such criticisms, given that the organization and the approach to collaborative global problem-solving that it represents, is under attack from President Trump, who decries it as a tool of China and threatens to withdraw financial support. And it is hardly the only organization that has made missteps at a volatile and tense time; the Centers for Disease Control and Prevention, to cite a domestic example, has, too, particularly in the area of testing. But the W.H.O. needs to be held accountable by those who recognize its value; trust is an asset that has to be guarded. And the W.H.O. is almost uniquely positioned to play a role in answering an overriding question: Why does the virus seem to be affecting different continents, countries, regions, and populations, even similarly situated ones, differently? (Another question that would benefit from international perspectives, as the pandemic stretches on, concerns the safest ways for people to participate in their countries’ political processes, from protesting to going to the polls.) Meanwhile, though, we have learned that, with some effort, we can flatten curves and save lives. “There’s enough stoppability in the virus—it’s not so transmissible that you cannot suppress,” Ryan said. “You can’t throw up your hands.” Or, for the moment, take off your mask in a crowded public place, even if you feel just fine.
A Guide to the Coronavirus
- The coronavirus vaccine is on track to be the fastest ever developed.
- What the coronavirus has revealed about American medicine.
- Recommendations for maintaining social distancing as the U.S. reopens, from socializing and using public bathrooms to wearing masks.
- Why remote work is so hard—and how it can be fixed.
- Seattle leaders let scientists take the lead in responding to the coronavirus. New York leaders did not.
- The long crusade of Dr. Anthony Fauci, the infectious-disease expert pinned between Donald Trump and the American people.
- What to read, watch, cook, and listen to under quarantine.
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