We have insufficient time and resources to conduct an in-depth analysis of the latest accounts of the effectiveness of mask-wearing, but we can offer a simple timeline in case others are interested and able to investigate.
8th NOVEMBER
The CATO Institute publishes a working paper entitled: Evidence for Community Cloth Face Masking to Limit the Spread of SARS‐CoV‑2: A Critical Review
It concludes:
'Of sixteen quantitative meta‐analyses, eight were equivocal or critical as to whether evidence supports a public recommendation of masks, and the remaining eight supported a public mask intervention on limited evidence primarily on the basis of the precautionary principle.' https://www.cato.org/working-paper/evidence-community-cloth-face-masking-limit-spread-sars-cov-2-critical-review#
This is consistent with a large body of other studies about mask-wearing, for example: https://swprs.org/face-masks-evidence/; https://www.professorhinkley.com/blog/sorry-oregon-your-mask-is-useless-according-to-the-science
The Guardian does not publish anything about this working paper.
18th NOVEMBER
The Guardian publishes a story with the headline: Mask-wearing cuts Covid incidence by 53%, says global study and the byline:
'Researchers said results highlight the need to continue with face coverings, social distancing and handwashing alongside vaccine programmes”
https://www.theguardian.com/world/2021/nov/17/wearing-masks-single-most-effective-way-to-tackle-covid-study-finds
The article is introduced like this:
“Vaccines are safe and effective and saving lives around the world. But most do not confer 100% protection, most countries have not vaccinated everyone, and it is not yet known if jabs will prevent future transmission of emerging coronavirus variants.
Globally, Covid cases exceeded 250 million this month. The virus is still infecting 50 million people worldwide every 90 days due to the highly transmissible Delta variant, with thousands dying each day.”
“Results from more than 30 studies from around the world were analysed in detail, showing a statistically significant 53% reduction in the incidence of Covid with mask wearing and a 25% reduction with physical distancing.
Handwashing also indicated a substantial 53% reduction in Covid incidence, although this was not statistically significant after adjusting for the small number of handwashing studies included.”
The Guardian does not offer any critical assessment of the research study, nor does it reference it in the article.
However a search reveals it: https://www.bmj.com/content/375/bmj-2021-068302
The authors claim to have screened 36,729 papers for possible inclusion but found only 6 on masks that they considered eligible. One of these was the Danish RCT mask study.
According to the Daily Sceptic this study: “…failed to show a statistically significant benefit to those randomised to wear high-quality surgical masks in both the intention-to-treat and per protocol (i.e., excluding those who reported not wearing masks as specified in the protocol) analyses. https://dailysceptic.org/2021/11/18/comprehensive-review-of-face-mask-studies-finds-no-evidence-of-benefit/
Another was an interview by telephone survey: https://gh.bmj.com/content/5/5/e002794?ijkey=c2c17aec821e202b8a42b8aeaf612c7f535ce4fc&keytype2=tf_ipsecsha. The study looked in to the effectiveness of mask-wearing in families of laboratory confirmed COVID-19 cases in Beijing and concluded that face mask use by the primary case and family contacts before the primary case developed symptoms was 79% effective in reducing transmission. It is not easy to follow the methodology of this paper, nevertheless the BMJ publish it.
The paper contains this passage:
“As the compliance of UFMU [universal face mask use] would be poor in the home, there was difficulty and also no necessity for everyone to wear masks at home. We recommended that those families with members who were at risk of getting infected with SARS-CoV-2 (such as ever having contact with a COVID-19 patient, medical workers caring for a COVID-19 patient or having a history of travelling to high risk areas) should apply UFMU to reduce the risk of household transmission.”
This seems to imply that the use of facemasks by the family members interviewed was sporadic and therefore that the study has no scientific merit.
We have not yet had time to consider the other four papers selected by the BMJ article.
Despite including this paper and the Danish study the BMJ article concludes:
“Overall pooled analysis showed a 53% reduction in covid-19 incidence (0.47, 0.29 to 0.75), although heterogeneity between studies was substantial (I2=84%)”
18th NOVEMBER
The Daily Sceptic publishes a summary of a study that arrives at the opposite conclusion to the Guardian article.
'The use of cloth facemasks in community settings has become an accepted public policy response to decrease disease transmission during the COVID-19 pandemic. Yet evidence of facemask efficacy is based primarily on observational studies that are subject to confounding and on mechanistic studies that rely on surrogate endpoints (such as droplet dispersion) as proxies for disease transmission. The available clinical evidence of facemask efficacy is of low quality and the best available clinical evidence has mostly failed to show efficacy, with fourteen of sixteen identified randomized controlled trials comparing face masks to no mask controls failing to find statistically significant benefit in the intent‐to‐treat populations. Of sixteen quantitative meta‐analyses, eight were equivocal or critical as to whether evidence supports a public recommendation of masks, and the remaining eight supported a public mask intervention on limited evidence primarily on the basis of the precautionary principle. Although weak evidence should not preclude precautionary actions in the face of unprecedented events such as the COVID-19 pandemic, ethical principles require that the strength of the evidence and best estimates of amount of benefit be truthfully communicated to the public.'
“Turning to clinical evidence, they summarise the findings of two gold-standard randomised controlled trials (RCTs), which indicate little to no benefit from mask-wearing.
'There have been two large-scale RCTs evaluating the use of facemasks at limiting the spread of SARS-CoV-2. One [DANMASK] failed to show a statistically significant benefit to those randomised to wear high-quality surgical masks in both the intention-to-treat and per protocol (i.e., excluding those who reported not wearing masks as specified in the protocol) analyses. The other [in Bangladesh] failed to find a statistically significant benefit to cloth masks, but found an 11% relative reduction in COVID-19 prevalence for surgical masks that was marginally statistically significant, with the confidence interval spanning 0% to 22%. In the latter trial, absolute reductions in COVID-19-like illness associated with mask-wearing were only 1% (reduced from 8.6% in control villages to 7.6% in intervention villages), while absolute reductions in symptomatic seroprevalence were less than 0.1% (from 0.76% in control villages to 0.68% in intervention village), raising questions about whether resources devoted to mask production, awareness, utilization, and enforcement could be deployed to greater public health benefit if directed at alternate interventions, such as vaccination, contact-tracing, or isolation.” https://dailysceptic.org/2021/11/18/comprehensive-review-of-face-mask-studies-finds-no-evidence-of-benefit/
The Guardian makes no reference to this article.
18th November
A related BMJ editorial is published: https://www.bmj.com/content/375/bmj.n2729. It concludes:
“What can we take from this new review? It might be reasonable to conclude that a bundle of PHSMs is modestly effective but that individual components cannot be reliability assessed owing to lack of adjustment for confounders or use of randomised or factorial trials.10 Face masks seem to have a real but small effect for wearer and source control, although final conclusions should await full reports of the trials from Bangladesh and Guinea-Bissau. However, the quality of the current evidence would be graded—by GRADE criteria11—as low or very low, as it consists of mainly observational studies with poor methods (biases in measurement of outcomes, classification of PHSM, and missing data), and high heterogeneity of effect size. More and better research are needed.”
Given that one of the authors is Susan Michie, who infamously declared that we should use ‘face masks forever’, the article is surprisingly circumspect. It most certainly does not concur with the Guardian’s statement that: Mask-wearing cuts Covid incidence by 53%, says global study.
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Many may find it a depressing sign of the times that a) the BMJ can accept an obviously deeply flawed ‘meta-analysis’ and b) the Guardian continues to ignore its responsibility to offer critical thinking and objective assessment.
It’s hysterical headlines must have caused incalculable anxiety and confusion during the course of this pandemic.
It is proposed that Andrew Gregory the Guardian health editor should offer an unconditional apology for his blatant failure to uphold the standards of decent journalism