Of Ventilators & Ventilation: Engineering the Coronavirus Out of the Workplace

By NORTIN HADLER, MD (2)

We are all reeling from the language of the COVID-19 pandemic: fatality rates, spread, PPE, distancing, pneumonia, anti-viral drugs, ventilators, second wave, vaccines, serological testing, etc. All of this focuses on the infection with the SARS-CoV-2 coronavirus, and for good reason. People are sick and dying from this infection. However, there is murmuring that will grow in volume as COVID-19 subsides: Will this happen again? Is the annual flu season to become more alarming in the future?  Will we forever be waiting for vaccines and anti-viral drugs with bated breath? 

If we step back and view this nightmare from the perspective of infectivity rather than infection, there may be a way out of this conundrum. Coronaviruses are one of several categories of virus with a proclivity for human respiratory infection. Coronaviruses join Influenza, Ebola, SARS and MERS as respiratory riboviruses. These viruses are tiny bundles, virions, containing a little RNA and not much else. Left alone, little happens. But if they manage to get into a target cell, they commandeer the cell’s metabolic machinery to do their malevolence. They get to their target cell because we inhale them as virions that are aerosolized or carried in the droplets that are produced when infected people exhale. Droplets that are not inhaled settle on surfaces, including surgical and N95 masks, where water evaporates freeing virions to aerosolize unless they are somehow bound to the surface. They are so tiny that even the N95 mesh is an inefficient barrier. One would need filters with such tiny pores that they would impede inhaling.

Infectivity of these riboviruses and probably severity of disease are dose dependent. The more virions one inhales the more likely one is infected. That’s the reason physical distancing is advised. However, these riboviruses retain infectivity for many hours on surfaces during which air currents can launch them and keep them afloat. That’s of little concern out of doors where they are diluted, but not indoors. Modern architectures and civil engineers are well aware of issues that relate to stagnation in built environments. HVAC systems are designed as a compromise between the need to recirculate air for the sake of efficient heating/cooling while turning to filters and air exchanges for the sake of air purity, particularly with regard to inert particulate materials. Concerns about airborne illnesses are seldom primary. In most hospitals, certain rooms are designed as “reverse flow” rooms for patients with contagious diseases with exhaust mechanisms so that the room’s air is released to outside the building, not back into general circulation in the building. Some operating rooms, particularly orthopedic surgical suites, have lamellar flow ventilation to decrease the likelihood of introducing an airborne pathogen along with orthopedic hardware. But otherwise hospitals and other workplaces are not designed with regard to infectivity.

Continue reading

Using Science Wisely:
Models, Evidence and the Politics of COVID19

By DAVID SHAYWITZ, MD (2)

As attractive as it is to think that science exists on a distinctive, untarnished, untrammeled plane, this idealization is dangerously misleading. Science is carried out by real people, within complex social organizations. Debates about science—often civil, occasionally acrimonious—on methods and meaning are the rule.

Which is as it should be: That’s how knowledge advances.

Ignoring what scientists have to teach us about COVID-19 would be a mistake. The virus is not a “hoax.”

But it’s also a mistake to default to the idea that we must “listen to Science,” as if there’s an unambiguous perspective that all researchers share and that all scientific data are established with an equal degree of certainty. This isn’t how science views itself. So we shouldn’t view it that way, either.

Within the universe of the present pandemic, some information seems very well established—the identification of the virus responsible for the condition, for example. Other data, including some very important essential facts, aren’t as clear.

We need to recognize and acknowledge these limitations.

Some people see these limitations are reason not to trust any of the information that comes out of the scientific establishment. For them, the failure of models to perfectly predict the trajectory of the pandemic was enough. What we’ve learned, said New York Post columnist Miranda Devine, is that “computer models are unreliable when it comes to predicting the future.” Instead of relying on supposed experts and their supposed models, she says, we should instead “trust the innate common sense of the American people.”

But there are more responsible ways to understand the problems with modeling.

Respected biostatistician Ruth Etzioni, at the Fred Hutch Cancer Research Center in Seattle, recently wrote that the latest version of the Institute for Health Metrics and Evaluation (IHME) model from the University of Washington “makes me cringe.” The changes revised the death projections significantly higher, and Etzioni argues that the modelers got there by making a number of obscure changes to the model, then presented these updates as reflecting simply the consequences of reduced social distancing.

Continue reading

The Reasonable Person’s Guide to Coronavirus

By ROB LAMBERTS, MD (3)

So this is what we are hearing:

  • COVID-19 is a serious crisis and you need to keep away from people and stay at home.
  • Things are better and we are re-opening restaurants, stores, churches, and hair salons.
  • The death tolls are an underestimate.
  • The death tolls are exaggerated.
  • No need to wear masks, as they don’t help.
  • You should wear a mask.
  • 100,000 Americans will die.
  • Make that 50,000.
  • The virus doesn’t spread through the air easily.
  • Simply being near someone who is talking can give you the virus.
  • Young people are basically immune from serious infection.
  • Anyone can die from it.
  • Hydroxychloroquine and Zithromax will cure it.
  • No, those don’t work.
  • A vaccine is in development.
  • A vaccine might not be available until late 2021, and it might not work great.

You get my point. It’s confusing and it’s frustrating. It’s like the old joke about the weather: if you don’t like the weather here, just wait 5 minutes. So if you hear something that bothers you, just wait 5 minutes and you’ll hear the opposite opinion about COVID-19. Why is this? Why can’t we agree? Why are facts being replaced by opinions?

The Nature of Science

The first thing I want to sayis that the nature of science is to get things wrong a lot in the path to getting things right. Contrary to popular perception, science is not about finding one answer and sticking with it because it is “true.” No, science is about gathering data through observation and experimentation and coming up with the best explanation for that data. More data often means that old explanations don’t float any more, but that’s OK because eventually, over time, we get things more and more right and come to a (hopefully) more truthful and useful answer.

6 months ago we knew almost nothing about this virus. 3 months ago, most of us were more concerned about fires in Australia, about all the rain we were getting, and about the Astros cheating. Yes, people were sounding the alarm about the seriousness of the virus, but few foresaw what ended up happening. Nobody was pushing for a vaccine 6 months ago, nobody was looking for medications to treat this disease. Nobody was storing away masks or making emergency plans for ventilators.

Continue reading