(This is the second part of a two-part post.)

The position of the European Centre for Disease Prevention and Control is similarly nuanced. It recommends masks for healthcare personnel and persons with symptoms, and it says a mask also “may help reduce the spread of infection . . . from infected individuals . . . before they develop any symptoms.” On the other hand, 

There is conflicting evidence on the protective effect for the wearer. . . . Based on the lack of evidence, it has so far not been recommended that people who are not ill or who are not providing care to a patient should wear a mask. . . . There is no evidence that non-medical face masks or other face covers are an effective means of respiratory protection for the wearer of the mask. . . . In one study, cotton surgical masks were associated with a higher risk of penetration of microorganisms and ILI compared to no masks.

According to this view, the only strong reason for the general public to wear a mask is not to protect yourself but rather to protect others from the small risk that you have contracted the virus without showing symptoms – if you have not just tested negative for the virus or positive for the antibodies.

Social trust

One advantage in dispensing with masks that Denmark and the other Nordic countries have is strong social trust among citizens and trust in the authorities – things that in the US are at about their lowest ebb in at least 50 years. They have small, relatively homogeneous and relatively well-educated populations with a high standard of living as well as a tendency toward conformism. Most Danes who could not work from home were excused from work with compensation for lost wages. With fewer people forced to work, there were fewer to avoid on the street and in workplaces.

In Denmark now, you see very few people wearing masks on the streets or in stores, less than 5 percent and most of them elderly. People stand in supermarket lines at two-meter markers on the floor. If you meet someone in an aisle or on a stairway, you move as far apart as you can and perhaps turn your head aside briefly as you pass. There is little controversy about it. A small lockdown protest group gathers before city hall occasionally, but nobody has bothered to interview them more than once. The cityscape is looking almost normal again. People are back on the streets, and shopping centers are crowded. Maybe a society doesn’t need masks if people respect one another’s space. It is ironic that Americans need masks because they don’t trust one another and the masks only exacerbate the polarization and increase their distrust.

Consulting big data

On June 1, The Lancet published a large metastudy on social distancing and face masks that concluded that masks do indeed have a protective effect for the wearer. The effect of N95 respirators was greater than with surgical masks or cloth masks, but the effect of the latter was significant, although the certainty of the conclusion was rated as “low”: “For the general public, evidence shows that . . . face masks are associated with protection, even in non-health-care settings, with either disposable surgical masks or reusable 12–16-layer cotton ones.”

A few days later, the WHO recommended that face masks should be worn (DK) in public when social distancing is not possible, for example on public transportation and in shops. Previously, the organization had said there was not enough evidence to require the general public to wear masks. Its recommendation is that people wear a fabric mask, not a medical mask, and one with “at least three layers of different material.” At the same time, it recommended that people over the age of 60 with underlying health conditions should wear medical masks and also cautioned that masks alone are not sufficient protection. People must continue to practice good hygiene and social distancing.

Not about to start now

Danish researchers responded to the announcement (DK) by saying that masks are not necessary in ordinary situations and the evidence for their value is slight. They add that masks are appropriate in situations where it is difficult to maintain social distancing, such as airplanes and public transport, but they doubted that the Danish government and Health Authority would change their recommendations now, after the infections have been declining steadily without the use of masks. So let’s hope the reopening of sporting events and gyms this week doesn’t lead to a new outbreak.