On The Lockdown, Masks And Aerosol Transmission

Ironically, our relative success in suppressing the exponential spread of Covid-19 is only increasing the pressure to ease back from those measures, on a regional basis at least. We seem set on course to start tentatively emerging from lockdown in about a fortnight, about the same time as community transmission is likely to be continuing to pick up steam. This partial surrender to the mounting economic (and political) pressure to ease the lockdown is likely to come at a cost.

If infections/deaths then spike, any temporary economic gains could be lost if we then need to head back into lockdown. Arguably, extending the lockdown fot a bit longer could buy us more time to obtain the resources that we will need to cope with the spike in the disease that will surely follow the relaxation. It is a really tough call. If the lockdown is economically unsustainable, the resumption of anything that resembles normal economic activity also looks extremely perilous – in that it is bound to increase the likelihood of the disease being taken back home to infect the vulnerable people who will still be sheltering in place.

In other words, the lockdown will have been the easy part. If we’re still using WW2 analogies, the lockdown has been the “phoney war” that occurred after the official declarations of war in 1939, but when nothing much then happened for the next eight months. For the past fortnight, much of the public debate (and media attention) has been to do with the rules and the reactions around the lockdown. There has been significantly less coverage of the adequacy of the preparations for what is to come.

It is almost as if the news cycle treats some aspects of the (lack of) preparation as old news, even when those issues remain unresolved. Currently, this country still has the same alarmingly low number of ventilators per capita. Unlike every other developed country, New Zealand has shown no urgency whatsoever about mounting a crash programme to build more of them, locally. The “news” that we had deployed Kiwi cunning to snare an extra 200 ventilators on the global market turned out to have been premature - and in any case a mere 200 more ventilators would still have been fewer than required in order to meet the likely demand for them on hospital wards. Have we really given up on building ventilators and really succeeded in buying (how many?) more from overseas? If so, what is their estimated time of arrival? And do we still think that having considerably fewer than 1,000 ventilators spread unequally across the country will actually be sufficient?

Masks, Aerosol Transmission

Similarly, the debate about whether the public should be wearing masks seems to have come and gone, unresolved. No one would query the need to prioritise giving the most effective masks to frontline health workers, as a key part of them having adequate PPE protections. Yet wasn’t there a factory in Wanganui that was reportedly churning out hundreds of thousands of masks a day? Is it still doing so, and at what point (and by what means) might the public be able to get access to some of them?

A week ago, Ministry of Health chief executive Ashley Bloomfield said that he was closely watching the US Center for Disease Control (CDC) and WHO rulings on this issue. Well the CDC has ended up recommending that the public should be wearing masks when out and about. Conversely, the WHO is standing by its recommendation to only wear a mask if you are sick or caring for someone who is sick. "Mask wearing by the general public is not among the WHO's recommendations," the organization has said. So, which organisation does our Ministry of Health think has got it right? Short of getting out the sewing machine and making some cloth masks themselves, the public currently has no way of gaining access to them.

At the heart of the masks debate lies another unresolved issue. Namely, does Dr Bloomfield think on his reading of the evidence that Covid-19 is transmitted by the aerosols expressed into the air when people breathe, talk or laugh - or does he think is it transmissible only by the droplets expelled when infected people cough onto people nearby, or onto surfaces that other people touch, and then infect themselves by touching their faces. The indications that Covid 19 seems to be two or three times more contagious than the flu would seem to support the case for aerosol transmission. Recent academic research and the White House science advisory panel have both come down on the side of aerosol transmission.

Areport from the National Academy of Science, Engineering and Medicine to the White House Office of Science and Technology Policy released on April 1 states that based on current research, SARS-CoV-2 may be spread through aerosols. The letter cites a recent study at the University of Nebraska Medical Center that found “widespread evidence of viral RNA in isolation rooms where patients with SARS-CoV-2 were receiving care” in air and surface samples. Even air collectors that were more than six feet away from patients detected the RNA, calling into question whether current social distancing guidelines are sufficient to prevent the spread of the disease.

Surely, this aerosols vs droplets debate has to be resolved before any rational decision can be made about easing the lockdown. If people really can pick up and transmit Covid 19 merely by breathing in the same air within a confined space, the last thing we’d want to do would be to start holding staff meetings in boardrooms, to brainstorm where the firm goes from here.

So far however, the MoH still tends to talk only about droplets and about the need to turn away and cough into elbows, wash hands thoroughly and maintain social distance. All very good advice, but arguably inadequate if aerosol transmission is a reality. When we talk together, we face each other. At this point, we need guidance from the MoH as to whether this can be done safely, especially in a confined space. And if masks can help to reduce aerosol transmission in public spaces, it becomes even more of an imperative for the public to wear them.

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