239 Experts With 1 Big Claim: The Coronavirus Is Airborne - The New York Times - 0 views
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The coronavirus is finding new victims worldwide, in bars and restaurants, offices, markets and casinos, giving rise to frightening clusters of infection that increasingly confirm what many scientists have been saying for months: The virus lingers in the air indoors, infecting those nearby.
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If airborne transmission is a significant factor in the pandemic, especially in crowded spaces with poor ventilation, the consequences for containment will be significant. Masks may be needed indoors, even in socially distant settings.
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Health care workers may need N95 masks that filter out even the smallest respiratory droplets as they care for coronavirus patients.
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Ventilation systems in schools, nursing homes, residences and businesses may need to minimize recirculating air and add powerful new filters.
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in an open letter to the W.H.O., 239 scientists in 32 countries have outlined the evidence showing that smaller particles can infect people, and are calling for the agency to revise its recommendations
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Whether carried aloft by large droplets that zoom through the air after a sneeze, or by much smaller exhaled droplets that may glide the length of a room, these experts said, the coronavirus is borne through air and can infect people when inhaled
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But the infection prevention and control committee in particular, experts said, is bound by a rigid and overly medicalized view of scientific evidence, is slow and risk-averse in updating its guidance and allows a few conservative voices to shout down dissent.
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“If we started revisiting airflow, we would have to be prepared to change a lot of what we do,” she said. “I think it’s a good idea, a very good idea, but it will cause an enormous shudder through the infection control society.”
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In early April, a group of 36 experts on air quality and aerosols urged the W.H.O. to consider the growing evidence on airborne transmission of the coronavirus. The agency responded promptly, calling Lidia Morawska, the group’s leader and a longtime W.H.O. consultant, to arrange a meeting.
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But the discussion was dominated by a few experts who are staunch supporters of handwashing and felt it must be emphasized over aerosols, according to some participants, and the committee’s advice remained unchanged.
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Dr. Morawska and others pointed to several incidents that indicate airborne transmission of the virus, particularly in poorly ventilated and crowded indoor spaces. They said the W.H.O. was making an artificial distinction between tiny aerosols and larger droplets, even though infected people produce both.
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Most of the samples in those experiments have come from hospital rooms with good air flow that would dilute viral levels.
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In most buildings, she said, “the air-exchange rate is usually much lower, allowing virus to accumulate in the air and pose a greater risk.”
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The W.H.O. also is relying on a dated definition of airborne transmission, Dr. Marr said. The agency believes an airborne pathogen, like the measles virus, has to be highly infectious and to travel long distances.
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Dr. Marr and others said the coronavirus seemed to be most infectious when people were in prolonged contact at close range, especially indoors, and even more so in superspreader events — exactly what scientists would expect from aerosol transmission.
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“We have this notion that airborne transmission means droplets hanging in the air capable of infecting you many hours later, drifting down streets, through letter boxes and finding their way into homes everywhere,”
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The agency lagged behind most of its member nations in endorsing face coverings for the public. While other organizations, including the C.D.C., have long since acknowledged the importance of transmission by people without symptoms, the W.H.O. still maintains that asymptomatic transmission is rare.
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Many experts said the W.H.O. should embrace what some called a “precautionary principle” and others called “needs and values” — the idea that even without definitive evidence, the agency should assume the worst of the virus, apply common sense and recommend the best protection possible.
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“There is no incontrovertible proof that SARS-CoV-2 travels or is transmitted significantly by aerosols, but there is absolutely no evidence that it’s not,
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So at the moment we have to make a decision in the face of uncertainty, and my goodness, it’s going to be a disastrous decision if we get it wrong,” she said. “So why not just mask up for a few weeks, just in case?”
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he agency also must consider the needs of all its member nations, including those with limited resources, and make sure its recommendations are tempered by “availability, feasibility, compliance, resource implications,” she said.
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if the W.H.O. were to push for rigorous control measures in the absence of proof, hospitals in low- and middle-income countries may be forced to divert scarce resources from other crucial programs.
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That’s the balance that an organization like the W.H.O. has to achieve,” he said. “It’s the easiest thing in the world to say, ‘We’ve got to follow the precautionary principle,’ and ignore the opportunity costs of that.”
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In interviews, other scientists criticized this view as paternalistic. “‘We’re not going to say what we really think, because we think you can’t deal with it?’ I don’t think that’s right,”
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Even cloth masks, if worn by everyone, can significantly reduce transmission, and the W.H.O. should say so clearly, he added.
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The W.H.O. tends to describe “an absence of evidence as evidence of absence,” Dr. Aldis added. In April, for example, the W.H.O. said, “There is currently no evidence that people who have recovered from Covid-19 and have antibodies are protected from a second infection.”
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The statement was intended to indicate uncertainty, but the phrasing stoked unease among the public and earned rebukes from several experts and journalists. The W.H.O. later walked back its comments.
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In a less public instance, the W.H.O. said there was “no evidence to suggest” that people with H.I.V. were at increased risk from the coronavirus. After Joseph Amon, the director of global health at Drexel University in Philadelphia who has sat on many agency committees, pointed out that the phrasing was misleading, the W.H.O. changed it to say the level of risk was “unknown.”
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But W.H.O. staff and some members said the critics did not give its committees enough credit.“Those that may have been frustrated may not be cognizant of how W.H.O. expert committees work, and they work slowly and deliberately,”