I want to quickly address this point.

The WHO recently issued updated technical guidance that found there is still no reliable evidence that Covid-19 is airborne. https://www.who.int/news-room/commentaries/detail/transmission-of-sars-cov-2-implications-for-infection-prevention-precautions 1/n

The WHO acknowledged there are examples of *specific settings* in which airborne droplets might spread Covid-19, such as the much-cited case of a cluster that began with an indoor choir rehearsal – but it notes these could still be explained by droplet transmission. 2/n

Recently the Vic CHO changed its message on masks, to ‘wear masks in settings where the 1.5m separation can’t be maintained.’ This is consistent with the WHO guidance and the AHPPC definition of two risk scenarios - face-to-face 15mins+ and indoor 2h+ with confirmed cases. /3

Calla’s tweet attributes confusion to the changing message. But to be quite honest, the confusion arises because mask crusaders have denied the evidence and accused WHO, AHPPC, and governments of a conspiracy to deny evidence of airborne transmission. Like… honestly. /4

We’ve seen governments reverse course and encourage or mandate the wearing of surgical masks or face coverings in a fairly specific scenario: when there is uncontrolled community spread, i.e. a high likelihood of encountering an active case of Covid-19 in public. /5

In this regard, recommending mask wearing is a ‘can’t hurt, might as well,’ last-ditch prevention recommendation. Not going to lie, seeing the Andrews government take that tack is doing me a real concern. However, that’s not the only reason it may have gone down that path. /6

It may just be a pragmatic response to the fact journalists and the public are repeatedly demanding to know why government hasn’t mandated masks yet. The answer to that question is technical and mask advocacy has become a moral crusade. In tactical terms, scissors, meet rock. /7

I’ve spent the last 16 years working in HIV prevention so let me tell you - the fact that a material protective device (e.g. masks, or condoms) is *simple* does not mean it is *easy* or *acceptable.* Messaging correct and consistent mask use is going to be a big challenge. /8

I want to conclude by noting that during this controversy over masks, public commentators like Norman Swan ignored casual, precarious work conditions among ‘essential’ workers – the situations and networks that allowed Victoria’s outbreak to get started and to spread. /9

We focused on masks as a silver bullet solution even as the Vic Gov announced the outbreak was spreading via family networks and at-home gatherings, which are events and settings where pretty much nobody is going to wear a mask. /10

So wearing masks in public is a good way to involve the community and for individuals to signal their commitment to ending the crisis.

But as population prevention it’s much more effective to *ban* the specific settings of risk, than to recommend masks as risk mitigation. -end-