Droplet or airborne?

THE impeachment trial of President Joseph Estrada in late 2000s — which was then a novel political box office hit in the Philippines — attracted so much attention that almost everyone became a lawyer overnight. This coronavirus disease 2019 (Covid-19) is commanding the same mass of cynosure, although in a morbid way, that almost everyone has become a medical expert in the last few days that we clicked and scrolled down webpages.

The Estrada trial created a spectacle from experts whose opinions, such as in the process of verifying an impeachment information, were diametrically opposed to each other. They differed despite having finished law from the same school, at about the same time, probably having read the same books and been taught by the same set of professors.

The clash of expert opinion in the field of medical science is also in full view today. The difference is that, now, less than precise notions can mean life or death. At stake then was the job of one man; at stake today are lives of thousands. It was fun then; it is horrifying now.

A key aspect, in which opinions differ among medical experts, pertains to the mode of Covid-19 transmission. Does the virus get transmitted by droplets or through particles flying in the air? The distinction and the frame by which it is communicated are crucial: on it depends the meaning of how people behave and take precautions to avoid being infected. State regulations do influence individual and social behavior, but their effectiveness can be either hampered or reinforced by what people know.

The World Health Organization (WHO) maintains that transmission of the virus happens in most, if not all, cases by droplets. Below is an excerpt of a “scientific brief” posted on its website three days ago:

“According to current evidence, Covid-19 virus is transmitted between people through respiratory droplets and contact routes.

“Droplet transmission occurs when a person is in in close contact (within 1 meter) with someone who has respiratory symptoms (e.g., coughing or sneezing) and is therefore at risk of having his/her mucosae (mouth and nose) or conjunctiva (eyes) exposed to potentially infective respiratory droplets. Droplet transmission may also occur through fomites in the immediate environment around the infected person. Therefore, transmission of the Covid-19 virus can occur by direct contact with infected people and indirect contact with surfaces in the immediate environment or with objects used on the infected person (e.g., stethoscope or thermometer).

“…In the context of Covid-19, airborne transmission may be possible in specific circumstances and settings in which procedures that generate aerosols are performed (i.e., endotracheal intubation, bronchoscopy, open suctioning, administration of nebulized treatment, manual ventilation before intubation, turning the patient to the prone position, disconnecting the patient from the ventilator, noninvasive positive-pressure ventilation, tracheostomy and cardiopulmonary resuscitation). In analysis of 75,465 Covid-19 cases in China, airborne transmission was not reported.”

Not all experts are satisfied with the way this knowledge is being propagated. A certain Dr. Donald Milton, who reportedly is an infectious disease aerobiologist at the University of Maryland’s School of Public Health in the United States, disagrees. He says: “I think the WHO is being irresponsible in giving out that information. This misinformation is dangerous.”

WHO’s advisory suggests that “droplets can travel only short distances through the air and either land on people or land on surfaces that people later touch.” This is the basis for the hygiene protocol that urges people “to wash hands frequently and not touch the face, because that could bring the virus into contact with the nose or mouth.”

While WHO acknowledges that airborne transmission might be possible “in specific circumstances and settings in which procedures that generate aerosols are performed,” and recommends “airborne precautions” when medical workers do those procedures, Milton is far from convinced, arguing that being a new virus, it is not appropriate to draw conclusions about how it is transmitted. ‘I don’t think they know, and I think they are talking out of their hats,’ he says, adding: “The epidemiologists say if it’s ‘close contact,’ then it’s not airborne. That’s baloney.”

The Centers for Disease Control and Prevention itself, a specialized agency of the US Department of Health and Human Services, cautions the American public that “Covid-19 is a new disease and we are still learning how it spreads.”

My own layman’s interpretation of what’s going on (which is immaterial in discussions as technical as these) is that if a bird’s feather can fly in the air for extended minutes (depending on which way the air is blowing), there is reason to believe that the virus, riding on extra light, almost invisible particles, can stay in the air for hours. In that case, even face masks, for as long as air can pass through them, provide little security and can even be treacherous in their offer of protection. There is greater danger in staying indoors where the air, constantly whipped up by ventilators and air-conditioning systems, allows the virus to float freely, than staying outdoors, where there is less concentration of the virus and hence also the probability of catching one is less.

That 12 out of 71 Covid-19 casualties in the Philippines are reported to be medical doctors (who undoubtedly were aware of mandatory precautions that must be taken under any situation) highlights the notion that many things about the disease are still unknown. It is also an up vote on Milton’s warning that there is risk in prescribing for something about which little is known.

WHO’s scientific study is based on analysis of 75,465 Covid-19 cases in China. It is not only a large sample size, but practically the whole universe (as statisticians would say), because the reported cases in China appear to have settled at less than 82,000. A sample that eliminates error in representation is always a researcher’s dream, except that the process of sorting out data sets of that size normally requires months, if not years, to finish. WHO completed the study in nine days, from February 16 to 24 of 2020.

The exigent need for life-altering information was addressed. But questions about its quality can be raised not only because peers in the medical field reject it, but more importantly because it gave authority to protocols that may have unnecessarily endangered human lives, including those of medical practitioners.

Calls have been heard for Tedros Adhanom Gebreyesus, the first politician and non-medical doctor to become director-general of WHO, to step down. He countered by saying that the online petitions urging him to resign for incompetence are being initiated almost solely by Taiwanese people. Mainland China lobbied for his election to the WHO top post and he is trying to imply that his detractors are more interested in politics than in health.

And, lest we forget, whether in an impeachment court or in medical wards, in politics or in health, opinions vary.