The Study
Cochrane Library: Physical interventions to interrupt or reduce the spread of respiratory viruses. The WebArchive version is here.
Lead author Tom Jefferson comes with impressive resume. He digs deep into data. For example, in 2012 he was lead researcher on a study into oseltamivir (Tamiflu). According to Wikipedia:
In 2012, Jefferson was the lead author of another Cochrane review of this data which concluded that oseltamivir [Tamiflu] did not reduce the number of hospitalizations caused by influenza. Jefferson said that this review also found no evidence that oseltamivir stopped complications from the disease.[6] The review is considered a landmark and is posted on the James Lind Library website[7] which illustrates the development of fair tests of healthcare. [my emphasis]
The critics of the Study: abc News here, Conversations, here, New York Times, here (with critique here and here), The Guardian, here (with critique here). The Washington Post, here (with critique here)
The critics of the critics of the Study: Vinay Prasad* MD, MPH, here, here and here. Kevin Bass, here. Kyle Lamb, here. Paul D. Thacker, here. Rod Liddle, here.
The sum of all the critics of the study is: the study doesn’t show masks don’t work. It shows that there is no evidence that they do. IOW “the absence of evidence is not evidence of absence”, which is taken apart by Dr Prasad in his pieces above, where he says the Cochrane study is simply following the same standards used for the study of all other medicines and non-medical interventions. Masks ought not be treated differently.
Then: “it’s apples and oranges” comparison, a critique by both the Conversations criticism and The Guardian, so seems they’ve cribbed off each other. In any case, it’s a fact that’s acknowledged by the Cochrane study authors themselves. They worked with what data they had. And that data was mixed. In total data from 78 RCTs, 11 of which were post the start of Covid. They acknowledge this is not enough and we need more. A question might be asked: why has the CDC or UK equivalents not done so? Especially in relation to masking by children, on which there’s not a single RCT?
Their criticism seems to be: you’re measuring people as they actually use masks, not how they should be used. Well, exactly. Because how people use masks is how people use masks. You can’t force compliance with some correct way of wearing masks. I know that from here in Hong Kong, where we had a very compliant and obedient population, but after a while masks were below noses and on chins. That’s just the reality. And that’s also the reality of population-wide mandates. People just get sick of them. It’s even the way with doctors and nurses who all say that they never wear the mask the whole day. It’s just too unconformable to be worn non-stop.
(ADDED: quite a while back I thought there might be a difference in how masks work in a laboratory and how the work in the Real World. And it turns out that’s true.)
Agenda: what would be the agenda of people saying “masks don’t work”? What skin in the game do they have?? Shorting mask-making stocks? Whereas C. Raina MacIntyre, lead author of the Conversation piece reveals in her Disclosure statement that she works for a mask manufacturer. Not that I’m saying that may have influenced her views in any way. Just sayin’. To repeat: there can be no agenda for finding against masks, for what’s the gain?
Bottom line: Cochrane Library is the best collection of data on mask effectives that we have to date. It’s the best we know on the available evidence. If you don’t like it, then have other studies go at it. The authors of the Cochrane study suggest this themselves. Even taking into account the critics, the most we can say, the most mask-friendly thing we can say is that the study doesn’t show that they definitely don’t work. At the very best that’s inconclusive. And it’s not the extraordinary evidence we need for the extraordinary demands that are made by mandates. As I said in my letter to the editor, here.
End of the day, mask wearing or not became one remains tribal. If you’re of the mask wearing tribe, you’ll look at the headlines in the critics of the Cochrane study and conclude that masks do work. And if you’re in the anti mask-mandate tribe, you’ll take comfort from the Cocharane study and keep on leaving your face open to the fresh air. And you’d be more right about that. Because you’d be following The Science. As far we know it today. Science might change conclusions. But for now, it’s Cochrane.
And, on this I think I’m done. Till next time. Mask you later!
*Vinay Prasad MD MPH Hematologist Oncologist. Associate Professor of Epidemiology and Biostatistics. www.vinayakkprasad.com
