This systematic review that searched for scientific evidence around the effectiveness of face masks in limiting the spread of COVID–19 among individuals who are not medically diagnosed with COVID–19, did not find any research studies that focused on the effectiveness of face mask use in tackling this specific virus in this specific population. Although the findings of this systematic review did not find any studies, having found that there is no scientific evidence that the current public health recommendations are based on regarding the use of face masks among this specific population, is an important finding that needs to be shared with the scientific community. It is important to bring attention to the lack of scientific evidence because the lack of scientific evidence questions the basis of contradicting and varying public health recommendations on face mask use that have been provided to those who are not medically diagnosed with COVID–19 around the world since the beginning of COVID–19 outbreak (provided in the background). In addition, bringing attention to the lack of scientific evidence on the effectiveness of face masks in limiting the spread of COVID–19 among this specific population can encourage novel and innovative research approaches to further investigate the subject. In this section, the author discusses the importance of the finding of this systematic review, in the context of providing public health recommendations amid an outbreak and the need for further research.
Evidence-based recommendations
The most important requirement for further research on this subject is the need for evidence-based recommendations on widely used precautionary methods such as face mask use during an outbreak like COVID–19. According to experts in the field of public health, there are multiple benefits to practicing evidence-based approaches in public health such as the increased availability of higher quality information on best practices, increased likelihood of successful prevention programs and policies, and increased efficiency in the use of public and private resources. [10] [11] [12] [13] [14] Current literature states that ideally public health professionals should always incorporate scientific evidence when planning and implementing programs, developing policies and evaluating progress, which also applies to when providing public recommendations. [14] [15] Therefore, it is best that recommendations are based on best available scientific evidence whether the recommendation is to wear or not to wear face masks in community settings among different types of sample populations. Recommendations that are not supported by scientific evidence can create controversy and confuse the public as well as health authorities around the world, creating contradicting and inconsistent recommendations. Such recommendations not only create confusion and controversy but also increase the risk of unnecessary spread of the infection.
As an example, in a situation where a pre-symptomatic or symptomatic individual with COVID–19 who has not yet been medically diagnosed, who is not wearing a face mask, coughs or sneezes without covering his/her face, they could be releasing respiratory droplets. The World Health Organization (WHO) states that “people can also catch COVID–19 if they breathe in droplets from a person with COVID–19 who coughs out or exhales droplets. This is why it is important to stay more than 1 meter (3 feet) away from a person who is sick.” [16] If these individuals are not wearing a face mask, the risk of spreading the infection through coughing or sneezing out droplets is higher. On the other hand, if healthy individuals in close proximity are not wearing face masks, they may be at a higher risk of contracting COVID–19 through respiratory droplets since transmission through droplets is one of the common methods of transmission of COVID–19. [16] Such kind of potential transmission is not rare especially in public transit during rush hour in any part of the world.
Health authorities in some countries may be implying that wearing a face mask may not be effective in protecting a healthy individual in this situation. [1] [2] [3] Meanwhile some health officials in countries like the Philippines have brought attention to the possibility of this kind of transmission and recommended the use of face masks. [5] The WHO provides a recommendation stating that “relatives or caregivers to individuals with suspected 2019-nCoV infection with mild respiratory symptoms should wear a medical mask when in the same room with the affected individual” suggesting that wearing a medical mask is useful in preventing the transmission of COVID–19 to those who are not medically diagnosed with the virus in some scenarios. [17] Although again, there is no scientific evidence to support this recommendation for this specific coronavirus according to the findings of this review. This recommendation has likely been provided to err on the side of caution by public health entities. However, it is questionable why the same recommendation does not apply to those who have not yet been exposed to the virus and are not relatives of an individual suspected with COVID–19, who can still be exposed to an infected individual in public spaces such as in the above public transit scenario. If face masks recommended above are effective in keeping out droplets between a sick family member and healthy family member, why are the same face masks ineffective in public spaces where there might be infected individuals who are not wearing face masks? Does wearing a face mask protect healthy individuals in close proximity in public spaces at least to some extent? Is not wearing a face mask at all in the situation in public transit beneficial than wearing one? These are questions that the general population likely have and should have clear answers to.
Currently, there is no known effective approach to prevent such type of transmission to healthy individuals other than to assume that pre-symptomatic or symptomatic individuals who have not yet been medically diagnosed follow recommended precautionary methods such as hand hygiene, cough and sneeze etiquette, and wearing a face mask. It is important to note here that asymptomatic, pre-symptomatic or symptomatic individuals who have not been medically diagnosed are impossible to distinguish from one another in terms of whether they carry COVID–19 and a risk of spreading the virus in public spaces. To be unsure of how to prevent the above type of transmission is dangerous during an outbreak like COVID–19 or a similar but worse type of coronavirus that humans may face in the future.
As demonstrated in the above information, the evidence behind recommendations provided regarding face mask use to those who are not medically diagnosed with COVID–19 is somewhat unclear and inconsistent, bringing some uncertainty around the current recommendations. Further scientific research on face mask use is imperative to answer the above questions and concerns to resolve the controversy and lack of clarity around face mask use and to provide evidence-based public health recommendations on whether to wear or not to wear face masks among different populations amid a fast-spreading outbreak such as COVID–19.
Providing recommendations on the use of face masks in the absence of evidence
When providing recommendations in the absence of evidence regarding a novel virus, where the knowledge about the virus is still evolving, there are important things to keep in mind. To answer concerns associated with the use of face masks, researchers and health care professionals must question if the potential risks associated with wearing face masks incorrectly outweigh the potential benefits of wearing face masks correctly when followed by other precautionary practices. Potential risks of face mask use as identified by health professionals around the world include: increased possibility of spreading germs due to the misuse of face masks such as touching the outside of the face masks and retouching underneath the face mask to touch the face; increased likelihood of people touching their own faces because of the face masks, for example to adjust the masks; establishment of a false sense of security among those who wear face masks; and ineffectiveness due to unfitting of face masks especially among children and those with facial hair. [17] [1] [2] [3] [9] [18] In the case where potential benefits of wearing face masks appropriately cannot be outweighed against the risks of wearing face masks due to the lack of evidence, taking actions to eliminate potential risks associated with wearing face masks may be a safer approach rather than recommending the public not to wear a face mask at all—that is only if face masks are effective in limiting the spread of COVID–19.
Furthermore, when providing recommendations to the public about the use of face masks to limit the transmission of COVID–19, it is important to give special consideration to vulnerable populations and those who are often around these vulnerable populations such as individuals in the community who have immunocompromised family members. People with pre-existing conditions such as cancer, diabetes, heart disease and renal or chronic lung disease appear to be more vulnerable to becoming severely ill with COVID–19 directly or through a family member. [19] [20] It may be best to err on the side of caution when making recommendations to the public regarding face mask use in the absence of evidence to reduce the risk of potential transmission to the most vulnerable populations.
Evidence and knowledge transparency of current recommendations with the public
According to public health experts, transparency during a health emergency is extremely important because information plays a vital role in promoting core public health objectives. [21] During a situation where the public is at risk of a real or potential health threat, there may be a lack of immediate treatment options, interventions may take time and resources may also be limited. [21] Public recommendations and guidelines, therefore, is the most important tool available in managing a risk in such a situation. [21] According to public health professionals, “proactive announcements and transparency in this context is seen not just as an organizational responsibility but as also the most effective way of seizing control of media reports, public discourse and customer relations associated with the event.” [21] Scholars in the field of public health ethics and pandemic influenza planning emphasize specifically the importance of transparency in managing infectious disease outbreaks. [21][22] During an infectious disease outbreak, “transparency not only provides individuals and communities with information needed to survive an emergency, but it is also an element of procedural fairness in decision-making and priority setting.” [21] [23] [24] Scholars further state that “it is also a necessary, if not sufficient, condition for accountable decision-making and for the promotion of public trust.” [21] Transparency about what is not known is as equally important as transparency about what is known to build and promote public trust. [21]
Therefore, in the case of the COVID–19 outbreak, whether recommendations are provided in the absence of evidence or whether they are evidence-based must be transparent to the public. Current confusion about the effectiveness of face mask use can be partially explained by the lack of evidence transparency of the recommendations with the public. Where there is evidence transparency, the public is more likely to understand what scientific evidence recommendations are based on and therefore, be more confident in adhering to provided recommendations. For example, in the case of medical professionals’ request to halt the hoarding of face masks among the public, merely saying “masks do not help” has not been helpful in preventing the public from continuing to buy face masks, perhaps unnecessarily. [25] [26] With scientific evidence of their ineffectiveness in limiting the spread of COVID–19 among those who are not medically diagnosed with COVID–19, public health professionals and entities can be consistent and confident when recommending the public not to buy face masks and as a result avoid situations such as running out of face masks for healthcare workers.
Similarly, knowledge transparency with the public is equally important in an outbreak. Some of the recommendations provided to the public suggest that the incorrect use of face masks may have potential risks which were discussed earlier. These potential risks can be minimized by educating the public about the potential risks and how to correctly use face masks to prevent the risks associated. A common concern brought up when providing current recommendations is about the false sense of security that face masks may bring to those who use them. [17] [2] [3] A false sense of security is the feeling of being safer than one really is. [27] In the context of COVID–19 and face mask use, a false sense of security means that the individuals may feel that they are safe from contracting COVID–19 because they are wearing face masks while that may not be the case. In the case of such concern, the public must be educated about the “false sense of security” that wearing a face mask may bring to individuals and how it may contribute to the increased risks associated with wearing face masks or neglecting other precautionary actions. In addition, some recommendations emphasize that other precautionary methods are more important than wearing a face mask while some suggest face masks are only effective in combination with other precautionary practices. [2] [9] All of the above information must be shared widely and effectively with the public worldwide through reliable media when making recommendations regarding the use of face masks. It is imperative to be transparent with the public about the current evidence and knowledge public recommendations are based on in order to successfully achieve the goals associated with the recommendations.
Global alignment on public health recommendations
Public health recommendations must align globally. Varying recommendations can have a negative effect on countries around the world, especially in developing countries. In some developing countries, there is a severe lack of dissemination of credible information to the public as well as a concerning lack of knowledge among the general population to be able to identify and distinguish credible information from noncredible information. In these populations, most people tend to trust what is typically seen on social media or other online platforms. For example, a consult physician in Sri Lanka says that, “containing the panic and dissemination of misinformation has proved tougher than fighting the actual disease [COVID–19].” [28] According to Health Analytics Asia, in Sri Lanka, India and Singapore, messages including false information regarding prevention methods of COVID–19 had widely circulated through online platforms such as WhatsApp. [29]
In the case of face mask use, when people in developing countries observe on online platforms a wide use of face masks to limit the spread of COVID–19 or recommendations advising the use of face masks, they may be likely to follow these recommendations without questioning the evidence behind the practices or recommendations. This may be the case especially when recommendations are coming from sources from developed countries. People may assume that the practices are evidence-based because they are coming from developed countries. Influenced by what they see on online platforms, the public of countries around the world may assume that merely wearing face masks will protect them from contracting COVID–19. Similarly, if there are recommendations to not wear face masks, those recommendations might also be followed without taking into consideration other advice that follow along such as practicing hand hygiene and respiratory hygiene.
In developing countries with less advanced health care systems, confusion due to varying recommendations can lead to having a worse negative impact on their population as well as healthcare systems. Considering these factors, global alignment on public health recommendations and decisions among public health professionals and entities is crucial when proving recommendations amid an outbreak such as COVID–19.
Future research
Further investigation into the effectiveness of face mask use among those who are not medically diagnosed with COVID–19 is important and timely for many reasons. If currently available face masks are not effective in limiting the spread of COVID–19 among this specific population or have significant limitations to its effectiveness, with advanced technology and innovations, researchers can investigate novel research approaches to invent and improve the efficiency of face masks to prevent the transmission of COVID–19 and similar or worse coronaviruses that the world may face in the future. It is important to note that only having a face mask as a physical barrier may not be sufficient as eyes are also exposed to viruses including COVID–19. [9] While investigating into the effectiveness of face masks may be beneficial in limiting the spread of COVID–19, further research may open doors to investigating, understanding, and designing more advanced personal protective equipment (PPE) for worse situations where PPE may be required in community settings. Furthermore, additional research can help identify and distinguish between the types of face masks that are best for different sample populations, and also address possible stigma and existing cultural differences associated with face mask use. Moreover, information about the effectiveness of face masks will provide health professionals insight into whether there is a need to advise global manufacturers to increase the production of face masks worldwide, which addresses growing concerns such as face mask hoarding among the public, limited availability of face masks for healthcare workers, and the need for mandatory control over supply and price of face masks through legislation in countries that recommend the use of face masks to limit the spread of COVID–19. [30] [31] [32]
Although COVID–19 has not been declared as a pandemic at the moment (25 Feb 2020), in case of a pandemic, knowing the effectiveness of masks ahead of time of the crisis would be extremely useful. While research surrounding the biology, epidemiology and behaviour of the new virus is extremely important and a priority at the moment, studying every method of prevention is equally important as prevention will not only provide the public with knowledge and instructions that they can rely on and confidently practice, but also save lives and reduce suffering and the expenditure of healthcare resources. This research is important, especially today because there is an immense use of face masks among the public around the world despite the uncertainty around the effectiveness of face masks. Such popular practices must be given immediate attention and studied thoroughly.