Tom Jefferson, senior associate tutor at the University of Oxford, is the lead author of a recent Cochrane review that has ‘gone viral’ on social media and re-ignited one of the most divisive debates during the pandemic – face masks.
The updated review titled “Physical interventions to interrupt or reduce the spread of acute respiratory viruses” found that wearing masks in the community probably makes little or no difference to influenza-like or covid-19-like illness transmission.
This comes off the back of three years of governments mandating the use of face masks in the community, schools and hospital settings. Just last month, the WHO upgraded its guidelines advising “anyone in a crowded, enclosed, or poorly ventilated space” to wear a mask.
Jefferson and his colleagues also looked at the evidence for social distancing, hand washing, and sanitising/sterilising surfaces — in total, 78 randomised trials with over 610,000 participants.
Jefferson doesn’t grant many interviews with journalists — he doesn’t trust the media. But since we worked together at Cochrane a few years ago, he decided to let his guard down with me.
During our conversation, Jefferson didn’t hold back. He condemned the pandemic’s “overnight experts,” he criticised the multitude of scientifically baseless health policies, and even opened up about his disappointment in Cochrane’s handling of the review.
DEMASI: This Cochrane review has caused quite a stir on social media and inflamed the great mask debate. What are your thoughts?
JEFFERSON: Well, it’s an update from our November 2020 review and the evidence really didn’t change from 2020 to 2023. There’s still no evidence that masks are effective during a pandemic.
DEMASI: And yet, most governments around the world implemented mask mandates during the pandemic…
JEFFERSON: Yes, well, governments completely failed to do the right thing and demand better evidence. At the beginning of the pandemic, there were some voices who said masks did not work and then suddenly the narrative changed.
DEMASI: That is true, Fauci went on 60 Minutes and said that masks are not necessary and then weeks later he changed his tune.
JEFFERSON: Same with New Zealand’s Chief Medical Officer. One minute he is saying masks don’t work, and the next minute, he flipped.
DEMASI: Why do you think that happened?
JEFFERSON: Governments had bad advisors from the very beginning… They were convinced by non-randomised studies, flawed observational studies. A lot of it had to do with appearing as if they were “doing something.”
In early 2020, when the pandemic was ramping up, we had just updated our Cochrane review ready to publish…but Cochrane held it up for 7 months before it was finally published in November 2020.
Those 7 months were crucial. During that time, it was when policy about masks was being formed. Our review was important, and it should have been out there.
DEMASI: What was the delay?
JEFFERSON: For some unknown reason, Cochrane decided it needed an “extra” peer review. And then they forced us to insert unnecessary text phrases in the review like “This review doesn’t contain any covid-19 trials,” when it was obvious to anyone reading the study that the cut-off date was January 2020.
DEMASI: Do you think Cochrane intentionally delayed that 2020 review?
JEFFERSON: During those 7 months, other researchers at Cochrane produced some unacceptable pieces of work, using unacceptable studies, that gave the “right answer.”
DEMASI: What do you mean by “the right answer?” Are you suggesting that Cochrane was pro-mask, and that your review contradicted the narrative. Is that your intuition?
JEFFERSON: Yes, I think that is what was going on. After the 7-month delay, Cochrane then published an editorial to accompany our review. The main message of that editorial was that you can’t sit on your hands, you’ve got to do something, you can’t wait for good evidence…. it’s a complete subversion of the ‘precautionary principle’ which states that you should do nothing unless you have reasonable evidence that benefits outweigh the harms.
DEMASI: Why would Cochrane do that?
JEFFERSON: I think the purpose of the editorial was to undermine our work.
DEMASI: Do you think Cochrane was playing a political game?
JEFFERSON: That I cannot say, but it was 7 months that just happened to coincide with the time when all the craziness began, when academics and politicians started jumping up and down about masks. We call them “strident campaigners.” They are activists, not scientists.
DEMASI: That’s interesting.
JEFFERSON: Well, no. It’s depressing.
DEMASI: So, the 2023 updated review now includes a couple of new covid-19 studies….the Danish mask study….and the Bangladesh study. In fact, there was a lot of discussion about the Bangladesh mask study which claimed to show some benefit….
JEFFERSON: That was not a very good study because it was not a study about whether masks worked, it was a study about increasing compliance for wearing a mask.
DEMASI: Right, I remember there was a reanalysis of the Bangladesh study showing it had significant bias….you’ve worked in this area for decades, you’re an expert…
JEFFERSON [interjects]… please do not call me an expert. I’m a guy who has worked in the field for some time. That has to be the message. I don’t work with models, I don’t make predictions. I don’t hassle people or chase them on social media. I don’t call them names… I’m a scientist. I work with data.
David Sackett, the founder of Evidence Based Medicine, once wrote a very famous article for the BMJ saying that ‘experts’ are part of the problem. You just have to look at the so-called ‘experts’ that have been advising government.
DEMASI: There were so many silly mask policies. They expected 2-year-olds to wear masks, and you had to wear a mask to walk into a restaurant, but you could take it off as soon as you sat down.
JEFFERSON: Yes, also the 2- meter rule. Based on what? Nothing.
DEMASI: Did you wear a mask?
JEFFERSON: I follow the law. If the law says I need to wear one, then I wear one because I have to. I do not break the law. I obey the law of the country.
DEMASI: Yeah, same. What would you say to people who still want to wear a mask?
JEFFERSON: I think it’s fair to say that if you want to wear a mask then you should have a choice, okay. But in the absence of evidence, you shouldn’t be forcing anybody to do so.
DEMASI: But people say, I’m not wearing a mask for me, I’m wearing it for you.
JEFFERSON: I have never understood that difference. Have you?
DEMASI: They say it’s not to protect themselves, but to protect others, an act of altruism.
JEFFERSON: Ah yes. Wonderful. They get the Albert Schweitzer prize for Humanitarianism. Here’s what I think. Your overnight experts know nothing.
JEFFERSON: There is just no evidence that they make any difference. Full stop. My job, our job as a review team, was to look at the evidence, we have done that. Not just for masks. We looked at hand washing, sterilisation, goggles, etcetera…
DEMASI: What’s the best evidence for avoiding infection?
JEFFERSON: I think your best shot is sanitation/sterilisation with antiseptic products. We’ve known for about 40 to 50 years that the inside of toilets, handles, seats for example, you recover a very high concentration of replication competent virus, it doesn’t matter what viruses they are. This argues for a contact/fomite mode of transmission.
Also, hand washing shows some benefit, especially in small children. The problem with that is, unless you make the population completely psychotic, they will not comply.
DEMASI: May I just ask a finer point on masks… it’s not that masks don’t work, it’s just that there is no evidence they do work…is that right?
JEFFERSON: There’s no evidence that they do work, that’s right. It’s possible they could work in some settings….we’d know if we’d done trials. All you needed was for Tedros [from WHO] to declare it’s a pandemic and they could have randomised half of the United Kingdom, or half of Italy, to masks and the other half to no masks. But they didn’t. Instead, they ran around like headless chickens.
DEMASI: I’ve worked as a political advisor, so I know that Governments don’t like to appear “uncertain,” they like to act as if they are in control of the situation….
JEFFERSON: Well, there’s always uncertainty. Masking became a “visible” political gesture, which is a point we make over and over again now. Washing hands and sanitation and vaccination are not overtly visible, but wearing a mask is.
DEMASI: Your review also showed that n95 masks for healthcare workers did not make much difference.
JEFFERSON: That’s right, it makes no difference – none of it.
DEMASI: Intuitively it makes sense to people though…. you put a barrier between you and the other person, and it helps reduce your risk?
JEFFERSON: Ahhhh the Swiss cheese argument…..
DEMASI: Well, the ‘Swiss cheese’ model was one of the most influential explanations for why people should layer their protection. Another barrier, another layer of protection? You don’t like the Swiss cheese model?
JEFFERSON: I like Swiss cheese to eat — the model not so much …It’s predicated on us knowing exactly how these respiratory viruses transmit, and that, I can tell you, we don’t know. There isn’t a single mode of transmission, it is probably mixed.
The idea that the covid virus is transmitted via aerosols has been repeated over and over as if it’s “truth” but the evidence is as thin as air. It’s complex and all journalists want 40 years of experience condensed into two sentences. You can quote the Swiss cheese model, but there’s no evidence that many of these things make any difference.
DEMASI: Why? How can that be?
JEFFERSON: It’s probably related to the way that people behave, it could be the way viruses are transmitted or their port of entry, people don’t wear masks correctly….no one really knows for sure. I keep saying it repeatedly, it needs to be looked at by doing a huge, randomised study – masks haven’t been given a proper trial. They should have been done, but they were not done. Instead, we have overnight experts perpetuating a ‘fear-demic.’
DEMASI: I’ve heard people say it would be unethical to do a study and randomise half of a group to masks and the other half to no masks….do you agree?
JEFFERSON: No, because we don’t know what effect masks will have. If we don’t know what impact they have, how can it be unethical? Strident fanatics have managed to poison this whole discussion and try and make it into a black and white thing…and rely on terribly flawed studies.
DEMASI: Thanks for the chat with me today.
JEFFERSON: You’re welcome, Maryanne.
Note: This interview was edited for clarity and brevity. Jefferson is co-author of Trust The Evidence
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