Coronavirus / Why face masks are an effective tool against the spread of the Covid-19 virus
COVID-19 has infected more than 29 million people globally resulting in untold number of tragic and premature deaths. As we move into autumn, scientists are predicting a second and perhaps even a third wave of the virus to sweep through the world’s populations.
In the second of a series of articles professor Deborah Briggs explains why at this stage in the pandemic the best and most effective strategies to protect ourselves and our immediate family members against infection is to rely on non-pharmaceutical interventions including face masks, social distancing, and diligently washing our hands.
I think that I can safely say that we are all anxiously awaiting news as to exactly ‘when’ we can anticipate having an effective vaccine to protect us against Covid-19. This question is especially urgent as we head into winter, flu-season, and the expected rise in influenza cases.
A vaccine against Covid would indeed solve the problems associated with the current annoyance that most of us are experiencing regarding not being able to be in close contact with as many members of our family, friends and colleagues as we would like to be meeting on a regular basis.
The ‘good news’ is that the development and production of a Covid vaccine is indeed moving forward at ‘warp speed’. However, the ‘not-so-good news’ is that most experts agree that an approved Covid vaccine is not likely to be available to the general public for several more months.
Effective therapies for patients suffering with Covid-19 are urgently needed and are indeed being investigated. However, there are many unanswered questions about the specific pathogenesis of SARS-Cov-2, the virus causing Covid-19, and so it is not prudent to even consider relying solely on treatment strategies as a means to stop the pandemic until we get the vaccine that we need.
Thus, at this stage in the pandemic, it is clear that the best and most effective strategies to protect ourselves and our immediate family members against infection is to rely on non-pharmaceutical interventions including face masks, social distancing, and diligently washing our hands etc.
The value of wearing face masks in public spaces has been a fairly hot topic of discussion since the beginning of the pandemic. However, there are an increasing number of published scientific studies indicating that non-pharmaceutical interventions such as wearing face masks can help to reduce the spread of Covid-19 in community settings.
When the pandemic erupted in December 2019 not much, if anything, was known about SARS-Cov-2 and its associated disease Covid-19. By January 2020, scientists had identified the disease as being caused by a coronavirus, it was a novel type of coronavirus for humans and the particular transmission features of this virus were unclear. Thus, there were no data specifically investigating whether wearing masks would prevent infection or even whether aerosol transmission was a high risk.
We are now close to a year into the pandemic and although scientists have (thankfully) collected a significant amount of data on the transmissibility of the virus, there is still much to learn about the pathogenesis of SARS-Cov-2 including why some populations are at higher risk of infection and death.
So, what are the latest data regarding the usefulness of face masks in preventing the spread of Covid-19? Can face masks reduce the spread of infected respiratory droplets caused by sneezes, coughing or even normal speech?
Several recent modeling studies have demonstrated that the use of face masks, as part of non-pharmaeutical interventions, will reduce community spread of Covid-19.
Additionally, one study just published in ScienceAdvances investigated 14 different types of face masks, (from N95 medical masks to knitted masks, neck fleece and bandana face coverings), as to their effectiveness in reducing the spread of droplets created during normal speech (see the link at the end of this article for more information).
The data from the experiments conducted in this study showed that fitted N95 and surgical medical masks were the most effective types of face coverings and reduced the spread of droplets to around 0.1% of the droplets normally created when no mask is worn.
That information should come as no surprise as medical face coverings have been used to prevent aerosol spread of infectious agents in hospital settings for a number of years. However, the study also showed that even face masks made from two-layered pleated cotton reduced the spread of respiratory droplets significantly.
In this study, knitted masks, fleece neck coverings and bandanas were much less effective. There was evidence (in this report as well as in other reports) that fleece face coverings may actually disperse droplets more effectively than not wearing a face covering at all and thus are not a good choice for face coverings as a preventive measure.
In summary, I have noticed that, for the most part, there is good compliance amongst Shetland residents when they visit shops, grocery stores etc. as far as wearing face masks is concerned. That is very encouraging.
We are all getting a bit (or maybe even more than a bit) “pandemic-weary” but it is critically important that we remember that this virus is not going away anytime soon.
The latest data indicate that there are now more than 29 million Covid-19 cases throughout the world with close to a million deaths reported. We cannot lose our way in the fight to prevent the spread of Covid-19 to our families, friends and neighbours.
As mentioned above, we are unlikely to have a vaccine available for several months and curative therapeutics are potentially even farther down the pipeline than is an effective vaccine at this point in time.
That means that our only option to prevent the spread of Covid-19 is to rely on non-pharmaceutical interventions and that means that all of us must continue to wear a face mask, maintain appropriate social distancing and wash our hands.
The full article in ScienceAdvances can be found here.
Professor Deborah Briggs has served as an expert to the World Health Organisation in the field of rabies prevention. She has provided expertise in the field of vaccine production and clinical trials for major pharmaceutical companies and continues to teach an online graduate level course in Global Public Health for Kansas State University. She lives in Bridge End, Burra.
More from Deborah Briggs:
For ‘herd immunity’ to be successful the process needs surveillance
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