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Coronavirus and the athlete: protection that counts!
From Peak Performance
In part 1 of this article, we looked at the biology and epidemiology of novel coronavirus, and explained why its virulence presents such a challenge for all of us. In part 2 we look at ways of minimising the chance of becoming infected by using physical barriers
Thanks to its extraordinary quarantine and social distancing measures, China appears to have reduced the incidence of new coronavirus cases down to a handful a day. In the rest of the world however, the rate of new infections is accelerating exponentially, with an average doubling time of around 4-5 days [https://www.worldometers.info/coronavirus/coronavirus-cases/#case-tot-outchina]. On its current trajectory therefore, we can expect the number of cases to rise well over 100-fold within the next month. Combined with widespread community transmission, this will mean a greatly increased chance that you will encounter environments where the virus is present. In this article therefore, we will look at ways to reduce the risk of infection if you are exposed to it.
Before we begin, let’s just recap some key points from the first part of this article. These can help inform our correct choices for minimising the risk of exposure going forward:
- Coronavirus is highly infectious with estimates of R0 between 2.2 and 6.7(1,2).
- Coronavirus can be spread by asymptomatic individuals who feel perfectly well.
- The virus is spread mainly via droplets (coughing/sneezing etc) but may also be spread via airborne transmission.
- The main routes of entry into the body are inhalation into the lungs, or via the epithelial tissues of the mouth, nose or eyes.
- The virus has a high degree of persistence on inanimate objects; thus the virus can readily be transferred from a surface (that has been coughed on sneezed on!) to one of the routes of entry above via the hands.
- The combination of high infectivity, asymptomatic transmission and a severe/critical complication rate of around 10% means that without measures such as social distancing, travel restriction and quarantines, the growth rate of serious cases has the capacity to swamp even the most advanced healthcare system.
Our responsibility as athletes
As someone who takes sport and training seriously, you might be wondering whether the level of concern expressed by health professionals is justified. However, the potential damage wrought by an unchecked spread of this virus would be immense. As we discussed in part one, around 5% of cases become critical, requiring ventilation and intensive care(3). Due to its high infectivity, an unchecked spread of the virus would crash the health system, resulting in the unnecessary deaths of hundreds of thousands or even millions of people. And whilst the strong and the fit are much less likely to be seriously affected by this virus, in a civilised society, we all have a duty of care to those who are more vulnerable that we are.
If that still doesn’t sound like a good reason to slow the spread of coronavirus, remember that younger adults are NOT immune. The case fatality rate for those between the ages of 10-40 years in an overwhelmed healthcare system is 0.2%, which is significant(4). And as the disease spreads in Europe, new data emphasises this point; for example, Professor Diedrick Gommers who is head of the Dutch Association of Intensive Care (NVIC) reported that earlier this week that over half of the patients currently in intensive care were in their 40s or younger(5).
Mount the defences
Hopefully, the information above explains why the spread of coronavirus needs to be slowed right down – not only to enable health systems to cope, but also to buy time for the development of a vaccine. Slowing down the spread of the virus essential means changing the environment so that the R0 is significantly reduced, which means less people are infected per unit of time. There are three main strategies that we can deploy to help achieve this goal:
- Physical barriers – placing physical barriers between ourselves and the virus such as the use of masks, gloves, protective clothing or even something as simple as using a tissue to open a the door of a public toilet or putting distance between you and the person you are interacting with.
- Chemical barriers/disinfection – using biocidal agents such as disinfectant, bleach and alcohol products to treat and clean any surface that you interact with – whether inside or outside of the home. This also includes effective hand washing!
- Avoidance strategies – altering your habits and routines (where at all possible) to remove or reduce your exposure to high-risk environments (this is what social distancing entails).
We will look at each of these strategies to see what the science recommends as best practice, but in this article, we will focus on physical barriers.
A physical barrier is the use of any device or object that physical impedes the virus from entering the body. Let’s start with perhaps the most controversial of all – masks. The job of a mask is to filter out particles and droplets from the air inhaled by the user. Since coronavirus virus particles (like all viruses) are extremely small (about 125nm in diameter – ie just 125 millionths of a millimetre), the smaller the size of particles that can be filtered out, the more effective the mask will be. Although there are a number of masks and respirators on the market, most of them that you might have seen mentioned in the media fall into two categories: surgical masks and N95 masks (see panel 1).
Surgical and N95 masks
A surgical mask (figure 1) is a loose-fitting, disposable device, which creates a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment. These are often referred to as face masks, although not all face masks are regulated as surgical masks. Note that the edges of the mask are not designed to form a seal around the nose and mouth.
Figure 1: surgical mask
An N95 respirator mask (figure 2) is a respiratory protective device designed to achieve a very close facial fit and very efficient filtration of airborne particles. The ‘N95’ designation means that when subjected to careful testing, the respirator blocks at least 95 percent of very small (300nm) test particles. The edges of the respirator are designed to form a seal around the nose and mouth. Surgical N95 respirators are commonly used in healthcare settings, and if properly fitted, their filtration capabilities of N95 respirators comfortably exceed those of surgical masks.
Figure 2: N95 mask
In my country (the UK), health professionals and the authorities have advised that masks are completely ineffective for protecting against coronavirus, even the N95 variety. However, in many other countries, particularly in Asia, masks of any type are considered mandatory for anyone venturing outside. So what’s the truth? When we look at the data from studies, there is some conflicting evidence on this topic, but this is perhaps hardly surprising as masks vary hugely in their design and filtration capacity.
Skeptics of mask use point to the fact that N95 masks only effectively filter down to 300nm particle size, whereas the coronavirus is half this size. However, mask advocates point to the fact that virus particles often come in an envelope of other liquids (eg sneeze, cough droplets etc), which bumps up droplet size to a level that is almost entirely blocked. They also point to the fact that N95 fibre masks tend to carry an electrostatic charge on the fibres, which produces a counter-intuitive increase in successful filtration.
The evidence for/against
Let’s start by stating two simple facts in favour of mask use. Firstly, their mere presence means that they can help stop you touching your mouth or nose with potentially virus-carrying hands – and that has to be a good thing. Secondly, they protect others; if you sneeze or cough with a mask on, the particles and droplets ejected into the air around you will be greatly reduced. But what about protection from external virus exposure? A large number of studies have been carried out on the effectiveness of mask use for preventing airborne and droplet respiratory infection. Due to space and time constraints, we can’t cite every study, but here are just a few of the recent findings:
- A systematic 2017 review study found that all masks helped to reduce the risk of contracting a respiratory infection, but that compared to surgical masks, N95 respirators conferred superior protection(6).
- In the same year, another study concluded that N95 respirators used as ‘airborne precautions’, provided superior protection for droplet-transmitted infections(7).
- The World Health Organization (WHO) and the U.S. Centres for Disease Control and Prevention (CDC) both recommend the use of a mask in low-risk settings and an N95 mask in high-risk settings (eg during aerosol generating procedures) to protect healthcare workers from seasonal influenza(8,9).
- Canadian research found that N95 respirators were more effective in preventing viral and bacterial infections compared with surgical masks. Moreover, several clinical guidelines recommended the use of N95 masks for managing patients with tuberculosis or highly contagious diseases, such as SARS and high-risk influenza(10). This is an interesting finding as we know that the SARS virus is extremely closely related to this novel coronavirus (SARS-Cov-2).
- Research found that when N95 masks were used by healthcare workers on infectious disease wards, it not only reduced their infection rates, but also conferred protection to their non-mask wearing colleagues(11).
- The protection afforded an N95 mask is not perfect. In one study, researchers found that despite passing fit-testing ,10% of N95 respirator users encountered breakthroughs with exposure to influenza virus(12).
Evidence direct from Wuhan
Overall, we can conclude that the overwhelming balance of recent scientific evidence is that while not perfect, wearing an N95 mask DOES afford significant protection from the risk of becoming infected when exposure to an infected person occurs. The evidence for surgical mask use is less robust, although they may still provide some protection, even if that is limited to reducing hand to mouth/nose contact. Finally, a fascinating new study on N95 mask use for the protection against novel coronavirus has emerged from China, which provides very persuasive evidence for N95 mask use(13).
In this study, researchers retrospectively collected infection data from 2nd to 22nd January at six departments from the Zhongnan Hospital of Wuhan University. In particular, they compared the infection rate of doctors and nurses treating patients in high-risk (confirmed infections) and low-risk (suspected infections) areas of the hospital. In the high-risk areas, the staff wore N95 masks. In the low-risk areas, the staff wore no masks. The results showed that despite working in the high-risk areas, none of the 278 N95 mask-wearing members of staff contracted the illness. In contrast, ten of the 213 non mask-wearing staff in the low-risk areas contracted the disease. Although it was likely that other procedures such as hand washing may have differed between the two groups, this study nevertheless suggests that N95 mask use can play an important role in reducing the risk of coronavirus infection.
Can the use of gloves – eg disposable latex or nitrile gloves – form an effective physical barrier against coronavirus? In theory, the answer is yes because the virus is too large to pass through the glove material. However, for two reasons, that’s only part of the story. Firstly, unless you have a wound or cut, the virus can’t gain entry to the body via the skin anyway. Secondly, when the hands are involved in viral infection, they are almost always used as a conduit – picking up viral particles from contaminated surfaces, which are then transferred to the mouth, nose or eyes when we touch our face.
Wearing gloves will not reduce the accumulation of viral particles on the hands. To illustrate this, a study last year investigated the magnitude of virus contamination on personal protective equipment, skin, and clothing of healthcare workers who cared for patients having acute viral infections(14). Overall, 31% of glove samples, 21% of gown samples, and 12% of face mask samples were positive for virus. Among the body and clothing sites, 21% of bare hand samples, 11% of scrub samples, and 7% of face samples were positive for virus. In other words, viral loads appeared to be higher on gloved hands than bare skin. There are however times when wearing gloves could be an advantage:
- As mentioned above, if you have a cut or abrasion on your hand, wearing gloves does present a useful barrier to infection.
- If you have no means of washing or disinfecting the hands (which we will cover in the next article) when out and about – for example after refuelling your vehicle at the gas/petrol station – wearing gloves followed by careful removal and disposable (see figure 3 below) gives you another option.
- Unless nails are kept short, viral particles can become trapped under the nails, requiring thorough washing to remove. For those with longer nails or those whose hands are becoming increasing dry and sore through constant hand washing (many I suspect!), glove use provides another option.
It’s not all positive for glove use however. Glove wearing could in fact engender a false sense of security, increasing the chance of the user touching his or her face while wearing them. Also, when gloves are used, it is still recommended to thoroughly wash the hands afterwards as there remains the possibility of virus particles transferring from the glove surface to the skin during removal.
Figure 3: Glove removal technique*
*Guidelines from the US Centre Disease Control (https://www.cdc.gov/vhf/ebola/pdf/poster-how-to-remove-gloves.pdf). Research shows that improper removal of gloves increase the risk of accidental infection(15).
Glasses and eye protection
As explained above, the eyes provide a route of entry into the body and infection for coronavirus particles. It makes sense therefore to ask whether eye protection in the form of glasses such as reading, driving or sunglasses can help reduce the risk of infection when someone is exposed to virus particles? In one way, the answer to this is ‘yes’; when you’re out and about, you’re much less likely to touch or rub your eyes with virus-contaminated hands when wearing glasses. And since touching contaminated surfaces then transferring virus particles to the face is a major route of coronavirus infection, the use of glasses (if you wear them anyway) makes sense. If you don’t normally wear glasses, the use of sunglasses while out and about could also be a good option.
However, while useful for reducing hand-to-face virus transmission, ordinary glasses are not particularly effective if you are exposed to high viral loads – for example, if you are caring for a family member who may be coughing or sneezing a lot. In a study of surgeons wearing eye protection equipment, the use of ordinary prescription glasses only reduced the risk of particle transmission to the eyes by 17%(16). This compared with a reduction of up to 97% for the wrap around plastic glasses and goggles. So, while ordinary prescription glasses may help reduce infection risk, for really effective protection, tight-fitting goggles are recommended.
When considering the use of barriers to prevent infection, don’t forget the simple things. Remembering just how persistent the coronavirus is on inanimate surfaces(17) such as door handles, keypads, light switches, electronic equipment buttons etc, there’s a high risk of transferring viral particles to the hands while carrying out ordinary day-to-day, routine activities such as shopping, withdrawing cash from an ATM, refuelling, using a public toilet etc.
One option is simply to take some disposable tissues or kitchen roll out with you when you leave the house. By holding a piece of tissue carefully across the palm of your hand, you can grasp door handles so that only the tissue touches the handle surface. Of course you need to ensure that you then scrunch up the tissue carefully afterwards, so that the surface that touched the handle is folded up on the inside, and that you don’t touch that surface. Similarly, you can operate keypads and buttons ‘through a tissue intermediary’ that you then dispose of straight after. Baby wipes can also be used instead of tissue. Thanks to their useful packaging, it’s possible to add extra protection by medicating them first with an effective antiviral disinfectant. However, chemical barriers and disinfection will be the topic of the next article in this series. Stay safe out there and look out for part three soon!
- J Med Virol. 2020 Mar 5. doi: 10.1002/jmv.25748. [Epub ahead of print]
- Sanche et al ‘The Novel Coronavirus, 2019-nCoV, is Highly Contagious and More Infectious Than Initially Estimated’ https://doi.org/10.1101/2020.02.07.20021154
- Zhonghua Jie He He Hu Xi Za Zhi. 2020 Mar 2;43(0):E027
- Data from Chinese Centre for Disease Control 2020
- Clin Infect Dis. 2017 Nov 13;65(11):1934-1942
- Influenza Other Respir Viruses. 2017 Nov;11(6):511-51
- Centres for Disease Control and Prevention. Prevention Strategies for Seasonal Influenza in Healthcare Settings. (http://www.cdc.gov/flu/professionals/infectioncontrol/healthcaresettings.htm)
- World Health Organization. Epidemic and pandemic prone acute respiratory diseases – infection prevention and control in health care. 2014http://www.who.int/csr/bioriskreduction/infection_control/publication/en/
- Canadian Agency for Drugs and Technologies in Health; 2017 Jun. CADTH Rapid Response Reports
- J Int Med Res. 2017 Dec;45(6):1760-1767
- Infect Control Hosp Epidemiol. 2018 Dec 18:1-3
- Association between 2019-nCoV transmission and N95 respirator use – medRxiv preprint doi: https://doi.org/10.1101/2020.02.18.20021881
- Infect Control Hosp Epidemiol. 2019 Dec;40(12):1356-1360
- Am J Infect Control. 2019 Sep;47(9):1146-1147
- J Bone Joint Surg Am. 2009 May;91(5):1050-4
- J Hosp Infect. 2020 Mar;104(3):246-251