Should I wear a surgical face mask?

I had this heated discussion / debate / argument with my brother - should a normal person wear a face mask during the Covid 19 pandemic? My brother lives in Europe, where wearing a surgical face mask is not the norm, even if one has respiratory symptoms. He has read up the literature and the evidence suggests that a normal person should not need to wear a face mask. I am based in East Asia and have lived through SARS. Wearing a face mask is now seen as secondary behaviour. I'm also a general practitioner, so wearing a face mask is pre-requisite for me (even though this practice is not seen in primary care physicians in the West).

So I have been ignoring people posting information without a source on social media and have been looking around. At moment, the Center for Disease Control and Prevention (CDC) and the World Health Organisation (WHO) recommend that a normal person should not need to wear a face mask. The evidence seems to support this; a recent review by the University of Hong Kong and published by the CDC's journal - Emergency Infectious Diseases - finds that studies cannot support the use of surgical face mask by normal people for influenza, or at most they have a modest impact on transmission.

Of course not every study is designed perfectly. If you look closer at the studies examined, you will find factors to pick at. The good points are that all of these studies are randomized control trials - the best sort of evidence a doctor would want. However the population sizes studied are quite small - they range from 84 patients and their household contacts to 1437 university hall residents recruited with 1297 university hall residents further analyzed. Only one of the studies was studied on the general population - 165 Australians going on the Hajj pilgrimage. Two studies were of university students residences and nine studies were on patients with their household contacts. These will be patients who are in close contact with their surrounding people, and not likely to mimic the general population.

The studies showed the impact of influenza and wearing face mask. Only one study (Macintyre et al. 2016) test for other respiratory viruses, including coronavirus. The study showed "a potential benefit of medical masks for source control, but is limited by small sample size and low secondary attack rates." Influenza is transmissible one day before the onset of symptoms. SARS-CoV-2 (the coronavirus causing Covid 19) has been shown to be transmissible during the incubation, which can last from 2-14 days. SARS-CoV-2 has been shown to be more transmissible and much deadlier compared to influenza. If you don't have symptoms and have Covid 19, when you sneeze and cough (as all people do from time to time, even if they don't have a cold), you are spreading the disease if you don't cover your nose or mouth.

There has been suggestions a surgical face mask will decrease the chances of infection because people will stop touching their face more, but if you are not use to wearing a surgical face mask (as most of the general population in North America and Europe are), you will tend to touch your face more since you have to adjust the face mask to make yourself feel comfortable.

In a recent Time article, David Hui, a respiratory medicine expert at the Chinese University of Hong Kong who studied the 2002 to 2003 outbreak of severe acute respiratory syndrome (SARS) extensively, points out that there can never be truly good evidence in situations like SARS and Covid 19 where you can find out if wearing surgical face masks will be useful or not.

Hui adds that the lack of solid evidence supporting the effectiveness of masks against the virus is no reason to dismiss its use, because there may never be definitive scientific proof. A properly controlled study would be impossible to conduct ethically, he explains. “You can’t randomize people to not wear a mask, and some to wear a mask, and then expose them all to the virus,” he says.

Most of the West haven't lived through something like this. Hong Kong went through SARS in 2003. There were 1755 cases in Hong Kong, second only to China, and 299 deaths. And these were not deaths in elderly people with medical conditions. SARS killed young health adults as well. I was a third year medical student at the time. Sixteen medical students were infected. Looking back, I should have been more scared than I was.

Ultimately it is a personal decision whether to wear a surgical face mask or not. Generally I would advocate it, seeing that Covid 19 is transmissible even when you are asymptomatic. If you are in close proximity of a Covid 19 case, have underlying medical conditions or caring for a person who has underlying medical conditions or have respiratory symptoms - wear a surgical face mask. Ultimately there is this point - there is no harm wearing one.