Evidence of aerosol transmission of COVID-19

I don’t normally blog about specific healthcare issues, but I’ve noticed a troubling omission from a number of reputable public health resources and their advice, and, frankly, some serious mistakes that have been made, because these sources have not yet incorporated important discoveries, and are therefore making recommendations which are not based on current evidence. No, I am not a doctor, but I do know how to read research papers carefully and look for confirming or disconfirming evidence.

We know, for sure, that COVID-19 spreads not only by droplet and contact, but also by aerosols. We’ve actually known that since the beginning, and we need to come back to that for public guidance and understanding, because I think that a number of people have lost the thread. Specifically, we knew this because healthcare professionals were rightly seeking good personal protective equipment including face shields and N95 masks when dealing with patients and ‘aerosolizing events.’ What this means for SARS-Cov2 care in particular, is that intubation and extubation tend to generate…spray. And it’s small enough that it gets carried about, more than the 6 foot / 2 meter recommendations.

What we’ve learned (or need to learn) is that aerosols are persistent, and they build up over time in enclosed spaces.

Understanding this should change your behaviour, and it’s important. It’s also important not to panic, in the sense of “oh no! It’s in the air! All is lost!”…which isn’t true.

Large Review Finds Good Evidence for Masks, Distancing in Stopping COVID-19 | MedPage Today

Good news: masks are a huge help.

A side “how to read this” note: calls for randomized trials is really people falling back on their comfort zone of “that’s how we test medicine” but it is *not* necessary or even possible for many interventions, so requiring randomized double-controlled studies introduces a different kind of bias: it excludes interventions where that isn’t possible, and adds a bias towards medications instead of prevention. This bias drives the costs of healthcare up, in that treatment rather than prevention is almost always more expensive. Other controls are possible, and observing after the fact “natural experiments” and meta-analyses like this also provides huge amounts of information that can be acted upon. In a pandemic, especially, wait and see on known effective preventative measures kills people. When the intervention is low risk and high payoff, just do it, and keep taking data to confirm or disprove whether it works!

That said: read the attached article.