Almost 5 months have passed since the first reported case of COVID-19 on the 17th of November 2019. Despite the resemblance to SARS, another respiratory syndrome caused for a different strain of coronavirus, the case numbers of COVID-19 already surpassed those of SARS by 30th Jan 2020.

The SARS outbreak between 2002 and 2003 resulted in over 8000 confirmed cases worldwide. While as of today, there are close to 2mil COVID-19 cases with a death toll rises to over 125,000.

The pandemic has triggered lockdowns in dozens of countries. It is clear that lockdown measures are slowing down the spread. But as with so many details surrounding COVID-19, there is not a clear-cut finding just yet.  

In particular, both the World Health Organization (WHO) and the Centre for Disease Controls (CDC) downplayed the widespread use of face masks as a preventive measure since the beginning of the outbreak.

The argument is that there is limited credible evidence that wearing a face mask by healthy individuals may be beneficial as a preventive measure.

There are other good reasons for the reluctance of health organizations to urge widespread mask use.

The shortage of medical face masks and PPE (personal protective equipment) for medical workers is a real concern. Throughout the outbreak, we have observed panic buying behaviors exhibited in different nations.

The assumption is that such advice might trigger panic buying of medical face masks among the general public rendering the medical workers defenseless without PPE.

Another potential issue WHO and other agencies have raised concerns about is that wearing a face mask could give a false sense of security. That could potentially undermine other preventive measures. There is also a risk of self-contamination from improper use of face masks.

Are these guidelines rooted in scientific rationales? Although some of the concerns by health agencies are valid, such assumptions and guidelines also contribute to the stigma that masks wearers are hoarders or ill, hence contagious.  

Change

Recently, the CDC had reversed its original policy on mask use. CDC now recommends that Americans should wear “cloth face coverings” as an additional preventive health measure. European Centre for Disease Prevention and Control (ECDC) recently released a technical report on the use of face masks in the community and no longer advises against the notion.

Other countries including Singapore, Austria, Czech Republic, Poland, Slovakia, and Bulgaria have either recommended or made it compulsory for everyone to mask up when venturing outside the safety of their own homes. Finland is the latest country to reverse its previous advice and encourage people to wear cloth masks.

The consensus is that although wearing a cloth mask might not protect you entirely from catching SARS-CoV-2, it might be useful in preventing you from spreading the virus if you are infected when combined with other preventive measures such as physical distancing and good hand hygiene.

Despite some countries adopting the change, some are still cautious sticking to the narrower guidelines. All the back-and-forth changes in guidelines and advice from government authorities have left the public confused.

Not enough evidence to support mask-wearing simply doesn’t mean that the act itself is ineffective.

Contrary to western countries, mask-wearing is the norm in Asian countries. In the East, mask wearers are not met with strange looks. And there is no shame.

East Asians have an ethic of wearing masks during outbreaks or even when one is sick. This practice is further strengthened after the SARS outbreak in 2003. It is also normal for people to wear a mask during cold or flu season.

Countries like Japan, South Korea, Hong Kong, and Taiwan were quick to act at the start of the outbreak. They have learned from their experience from the SARS outbreak. The spread of COVID-19 has slowed from the initial pace in these four countries considerably compared to other western countries.

There is debate over whether the spread has slowed because of the lack of testing or simply the result of stringent lockdown measures and contact tracing.

Even if there is no evidence to prove the effectiveness of widespread mask use, for many Asian countries, the attitude is “it is better to be safe than sorry later”.  

New evidence

There is increasing evidence that the shedding of SARS-CoV-2 can occur during asymptomatic and pre-symptomatic stages of the infection. A person infected with the virus might exhibit mild or no symptoms yet unknowingly spread the virus.

Preliminary evidence based on cases in China indicated the occurrence of pre-symptomatic transmission of the novel coronavirus. A recent report also indicated the evidence of pre-symptomatic transmission in Singapore.

Together with other reports from China, the evidence supports the possibility of viral shedding in asymptomatic and pre-symptomatic infected individuals.

These findings further increase the challenges nations are already facing. To control the pandemic, the containment measures might need to be escalated. For example, health officials might consider extending contact tracing to the period before the onset of any symptoms.

Main caveats

There are several pros and cons of widespread face mask use. Among them, three caveats stood out the most.

First, government and health authorities should ensure that medical face masks and respirators (e.g. N95) are reserved for healthcare providers, given we are already facing a shortage of PPE worldwide.

The next caveat would be the false sense of security mask use might offer. This could potentially deter the community from following stringent lockdown and distancing measures. Hence, mask use should be considered just a complementary measure and by no means a replacement for existing preventive measures.

Lastly, the improper use of a face mask could lead to self-contamination and increase the risk of further transmission. For this, adequate education campaigns can improve awareness and urge the appropriate use of face masks.

If authorities are to loosen the lockdown soon for economic reasons, perhaps widespread mask use can be part of the exit solution coupled with other preventive measures.

Everyone should continue practicing good hand hygiene, respiratory etiquette, and physical distancing. It is unlikely that society can return to the previous norm.

Social or more accurately, physical distancing measures will likely be the new norm.

For now, stay home and stay safe!

References:
1. Hu, Z. et al. Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing, China. Sci China Life Sci (2020).
2. Wang, Y. et al. Clinical Outcomes in 55 Patients With Severe Acute Respiratory Syndrome Coronavirus 2 Who Were Asymptomatic at Hospital Admission in Shenzhen, China. The Journal of Infectious Diseases (2020).
3. Wei, W.E. et al. Presymptomatic Transmission of SARS-CoV-2 – Singapore, January 23-March 16, 2020. MMWR Morb Mortal Wkly Rep 69, 411-415 (2020).