Norwegian researchers find masks associated with more Covid infections, blame bias not masks

A new peer-reviewed study by Norwegian researchers has recently been published titled “Association between Face mask use and Risk of SARS-CoV-2 Infection – Cross-sectional study”. In case you didn’t already know, a cross-sectional study “is a type of observational study that analyzes data from a population, or a representative subset, at a specific point in time”, in this case early 2022. However, the data were collected during an RCT of wearing glasses. So what kind of association did they find?

We examined the association between face masks and risk of infection with SARS-CoV-2 using cross-sectional data from 3,209 participants in a randomized trial of using glasses to reduce the risk of infection with SARS-CoV-2. Face mask use was based on participants’ response to the end-of-follow-up survey. We found that the incidence of self-reported COVID-19 was 33% (aRR 1.33; 95% CI 1.03 - 1.72) higher in those wearing face masks often or sometimes, and 40% (aRR 1.40; 95% CI 1.08 - 1.82) higher in those wearing face masks almost always or always, compared to participants who reported wearing face masks never or almost never.

Oh dear. And these are the results after controlling for observable confounders. In the raw data, regular mask-wearers had a 74-75% higher risk of testing positive for Covid.

The crude estimates show a higher incidence of testing positive for COVID-19 in the groups that used face masks more frequently, with 8.6% of participants who never or almost never used masks, 15.0% of participants who sometimes used masks, and 15.1% of participants who almost always or always used masks reporting a positive test result. The risk was 1.74 (1.38 to 2.18) times higher in those who wore face masks often or sometimes and 1.75 (1.39 to 2.21) times higher in those who wore face masks almost always or always, compared to participants who reported never or almost never wore masks.

Well, this is embarrassing for the pro-maskers, isn’t it? Frankly, I think you’d need a heart of stone not to laugh at these results.

So does this study prove that masks actually increase your risk of catching Covid? No. The authors mention various possible biases that could have affected the results.

A major limitation of our study is the non-randomized, cross-sectional study design. It may be that mask wearers were more prone to wear masks to protect others from their own infection. This reverse causality may explain the positive association between risk of infection and mask usage, and could be supported by the finding that participants reporting to wear masks also were more likely to test themselves for COVID-19. Furthermore, there may be other behavioral differences related to perception of risk or occupation that we did not observe, that are linked to the likelihood of wearing mask or to the likelihood of being tested for COVID-19 when symptomatic. There is also the possibility that mask wearers feel somewhat protected and thus change their behaviors to not observe social distancing, so that any benefit of masking is offset by increased exposure. Lastly, our main outcome was based on self-report, which is also a possible source of bias.

I think these are all valid points. Norwegians who did/didn’t wear masks in early 2022 probably did work in different jobs and behave differently outside of work too, and some may have worn masks because they tested positive. Without randomising people into groups that are as identical as possible beforehand, like in the Danish mask RCT that found no effect, researchers risk finding all sorts of spurious correlations and associations. So I totally agree with the authors that “caution is imperative when interpreting the results from this and other observational studies on the relationship between mask wearing and infection risk.”

However, governments worldwide forced people to wear masks on the basis of observational studies far poorer than this one, such as the US CDC’s classic study of two hairstylists.

If we’ve learned anything since 2020, it’s that there’s no study too shoddy that politicians and other public officials won’t use it as an excuse to force you to do whatever they want you to do.

So should we raise the evidence bar necessary to clear before similar mandates and restrictions can be implemented in the future? For example, requiring statistically significant results from well conducted RCTs? That would be a start, but it probably wouldn’t be enough to save us from future tyranny or stupidity.

Take, for example, the RCT of wearing glasses the above data came from. People who wore glasses had a statistically significant 10% lower risk of self-reported respiratory infections and a 17% lower risk of self-reported Covid infections which almost reached significance. But even if the results for self-reported Covid infections had reached significance too, does anyone think these results they would justify glasses-wearing mandates? Ultimately, the decision to wear masks, glasses, or a stick-on mustache should be left to the individual: my face, my choice.

Put simply, if we want to avoid the authorities again putting ill-conceived restrictions on our actions, we need to put restrictions on the authorities’ ill-conceived actions.