As of June 22, 2020, which is the second day of summer, COVID-19 cases are rising precipitously in America, in particular in "sun belt" states, including California, Texas, Florida, Arizona, and other southern U.S. states typically hit by strong summertime winds. If viral matter can be prevented from being spread by face masks covering mouth and nose, then can viral matter be passed by perspiration on the body?
Spread of Coronavirus (SARS-CoV-2) through aerosols of perspiration (sweat): Theoretically possible but no scientific evidence to date.
Based on lay-press reports of SARS (cuased by SARS-CoV1) transmission by sweat (1), publications mention that SARS-Cov-2 (causing COVID-2) was detected in the sweat of COVID-19 patients (2-3).
However, there is no scientific publication proving transmission through sweat.
If this was the case, there must have been huge surge of cases, in hot and humid climates where people perspire a lot.
1. SARS linked to sweat https://www.nature.com/articles/news040503-13
2. Article A new threat from an old enemy: Re‑emergence of coronavirus (Review)
3. A Review : Outbreak of Corona - J Med Biomed App Sci 8 (4), 354–357 (2020)
1. Routes of transmission
Infection control advice is based on the reasonable assumption that the transmission characteristics of COVID-19 are similar to those of the 2003 SARS-CoV outbreak. The initial phylogenetic and immunologic similarities between COVID-19 and SARS-CoV can be extrapolated to gain insight into some of the epidemiological characteristics.
The transmission of COVID-19 is thought to occur mainly through respiratory droplets generated by coughing and sneezing, and through contact with contaminated surfaces. The predominant modes of transmission are assumed to be droplet and contact.
During AGPs there is an increased risk of aerosol spread of infectious agents irrespective of the mode of transmission (contact, droplet, or airborne), and airborne precautions must be implemented when performing aerosol generating procedure (AGPs), including those carried out on suspected as well as confirmed cases of COVID-19.
Initial research has identified the presence of COVID-19 virus in the stools and conjunctival secretions of confirmed cases. All secretions (except sweat) and excretions, including diarrhoeal stools from patients with known or possible COVID-19, should be regarded as potentially infectious.
2. Incubation and infectious period
The incubation period is from 1 to 14 days (median 5 days). Assessment of the clinical and epidemiological characteristics of COVID-19 cases suggests that, similar to SARS, most patients will not be infectious until the onset of symptoms. In most cases, individuals are usually considered infectious while they have symptoms; how infectious individuals are, depends on the severity of their symptoms and stage of their illness.
The median time from symptom onset to clinical recovery for mild cases is approximately 2 weeks and is 3 to 6 weeks for severe or critical cases. There have been case reports that suggest possible infectivity prior to the onset of symptoms, with detection of SARS-CoV-2 RNA in some individuals before the onset of symptoms.
Further study is required to determine the frequency, importance and impact of asymptomatic and pre-symptomatic infection, in terms of transmission risks.
From international data, the balance of evidence is that most people will have sufficiently reduced infectivity 7 days after the onset of symptoms.
Please see guidance for stepdown of infection control precautions within hospitals and discharging COVID-19 patients from hospital to home settings. Guidance is also available from Public Health Wales (PHW) and Health Protection Scotland (HPS).
3. Survival in the environment
In light of limited data for SARS-CoV-2, evidence was assessed from studies conducted with previous human coronaviruses including MERS-CoV and SARS-CoV. Human coronaviruses can survive on inanimate objects and can remain viable for up to 5 days at temperatures of 22 to 25°C and relative humidity of 40 to 50% (which is typical of air-conditioned indoor environments).
Survival on environmental surfaces is also dependent on the surface type. An experimental study using a SARS-CoV-2 strain reported viability on plastic for up to 72 hours, for 48 hours on stainless steel and up to 8 hours on copper. Viability was quantified by end-point titration on Vero E6 cells. Extensive environmental contamination may occur following an AGP.
The rate of clearance of aerosols in an enclosed space is dependent on the extent of any mechanical or natural ventilation and the size of the droplets created. The greater the number of air changes per hour (ventilation rate), the sooner any aerosol will be cleared.
The time required for clearance of aerosols, and thus the time after which the room can be entered without a filtering face piece (class 3) (FFP3) respirator, can be determined by the number of air changes per hour (ACH) as outlined in WHO guidance; in general wards and single rooms there should be a minimum of 6 air changes per hour, in negative-pressure isolation rooms there should be a minimum of 12 air changes per hour.
Where feasible, environmental decontamination should be performed when it is considered appropriate to enter the room or area following an AGP without an FFP3 respirator. A single air change is estimated to remove 63% of airborne contaminants, after 5 air changes less than 1% of airborne contamination is thought to remain. Clearance of infectious particles after an AGP is dependent on the ventilation and air change within the room. In an isolation room with 10 to 12 air changes per hour (ACH), a minimum of 20 minutes is considered pragmatic. In a single room with 6 ACH this would be approximately one hour.
"The transmission of COVID-19 is thought to occur mainly through respiratory droplets generated by coughing and sneezing, and through contact with contaminated surfaces. The predominant modes of transmission are assumed to be droplet and contact."
I don't see how any of the epidemiological evidence supports this at all. COVID is spread aerially by close physical contact between persons in crowded indoor settings. If it was spread via droplets we would by now have clear clinical evidence for the community efficacy of masks, so the infective carriers must be much smaller than droplets. There is also massive evidence for spread via asymptomatic persons.
Anthony G Gordon ,
Thank you so much for your articulate and reasoned answer!
Seems yes...
Morawska, L., Tang, J. W., Bahnfleth, W., Bluyssen, P. M., Boerstra, A., Buonanno, G., ... & Wierzbicka, A. (2020). How can airborne transmission of COVID-19 indoors be minimised?.
Bahl, P., Doolan, C., de Silva, C., Chughtai, A. A., Bourouiba, L., & MacIntyre, C. R. (2020). Airborne or droplet precautions for health workers treating COVID-19?. The Journal of infectious diseases.
D A Gayan Nayanajith ,
I am grateful for your list of articles on how airborne transmission of COVID-19 can be minimized and on airborne or droplet precautions for health workers treating COVID-19. Thank you very much!
Ijaz Durrani
,Thank you very much for the quote and link, as follows:
" Sweat could actually help prevent the transmission of COVID-19 (among other things) says Dr. Adam Friedman, Professor and Interim Chair, Department of Dermatology at The George Washington University and IHhS faculty member. "Sweat," he says, "has some inherent antimicrobial activity. The sweat nitrate becomes acidified when it hits the skin, generating nitric oxide, which is one of the most potent broad-spectrum antimicrobial agents. In fact, gaseous nitric oxide is being currently studied as a potential treatment for some of the severe complications related to COVID-19." https://www.globenewswire.com/news-release/2020/07/07/2058877/0/en/Can-Sweat-Spread-COVID-19.html
Zeina A.Althanoon ,
I wish to thank you very much for your very detailed and informative paragraphs in answer to this discussion question!
With best regards and all good wishes.
Anthony G Gordon ,
Thank you for your comments regarding the spread of COVID-19 through visible coughing and sneezing droplets versus through airborne viral invisible matter. The wearing of cloth coverings by both symptomatic and asymptomatic individuals does definitely stop widespread infection. Best regards.
There is no scientific evidence regarding transmission of SARS-CoV-2 through air-borne perspiration droplets.
A bigger issue we have found here in California, is tobacco smoke that can get inhaled through most masks, and the person smoking who is infected, can have Covid hitch-hikers on particles of that tobacco smoke, and the tobacco smoke carry them a very long distance, perhaps 100-200 meters in the smoke cloud?
Craig Carlton Dremann ,
Thank you for raising the issue of COVD-19 and smoking. The following is an item on the Internet, and there are many similar anti-smoking articles:
Coronavirus and Smoking
IN THIS ARTICLE
- Are Smokers More Likely to Get COVID-19?
- Are Smokers at High Risk of Severe COVID-19 Infections?
- Are Vapers at High Risk of COVID-19?
- Are Marijuana Users at High Risk of COVID-19?
- Can Secondhand Smoke Spread the Coronavirus to Others?
- How Can Smokers Lower Their Coronavirus Risk?
Certain groups of people are at higher risk of getting seriously sick from COVID-19. If you smoke or vape, you're one of them. That means it's even more important for you to take steps to protect yourself from the new coronavirus.
Are Smokers More Likely to Get COVID-19?
When you smoke or vape, your fingers touch your lips. This raises the chance that the virus will spread from your hand to your mouth.
If you use a smoking product like a water pipe, you may share its mouthpieces or hoses with others. If you use it with someone who’s infected, you could get sick, too.
If you use a smoking product like a water pipe, you may share its mouthpieces or hoses with others. If you use it with someone who’s infected, you could get sick, too.
Smoking and vaping can also lower your immunity to respiratory infections. One study even found that e-cigarettes suppress immune cells in your nose. They also destroy the cilia in your lungs. Cilia are tiny, hair-like structures that trap viruses and debris and sweep them out of your airways. They're one of your body’s main defenses against infection. When they're damaged, they're less able to prevent the virus from settling into your lungs.
The new coronavirus enters cells in your lungs by binding to things called ACE 2 receptors. Researchers found that cigarette smoke increases your ACE 2 levels, though it’s not clear what effect this might have on your chances of getting COVID-19.
Are Smokers at High Risk of Severe COVID-19 Infections?
If you smoke, you may already have lung problems. They make you more likely to get very sick from COVID-19 as the coronavirus attacks your lungs.
When smokers’ lungs are exposed to flu or other infections that affect their airways, they can get much sicker than nonsmokers. If your lungs are already damaged, they may not be able to provide you with enough oxygen or to use oxygen the way they should. Damage to the cilia in your lungs can also make it harder for them to clear out things like mucus.
Smokers are more likely to get serious lung conditions such as pneumonia. They're also at higher risk of a complication called acute respiratory distress syndrome (ARDS), in which fluid builds up in the tiny air sacs in your lungs. This means your lungs can't fill with enough air. Less oxygen gets to your bloodstream and organs. This can lead to organ damage or even death.
One Chinese study of people who had COVID-19 and were hospitalized with pneumonia found that the odds that the disease would get worse were 14 times higher for those with a history of smoking.
People who smoke are more likely to have chronic obstructive pulmonary disease (COPD) and heart and blood vessel disease, which raises their risk of serious complications.
Human history is witnessing a very strange time fighting an invisible enemy; the novel COVID-19 coronavirus. Initially observed in the Wuhan province of China, now rapidly spreading around the world, the disease has taken the lives of millions of individuals. COVID-19 spreads through transmission i.e. from people to people. A tiny droplet from the nose or mouth of a person with COVID-19 can affect millions together in contact. The unaffected person becomes prone to this disease by personal contact or by contact through contaminated surfaces including paper, cardboard, steel, glass wood, pen, mobile etc. In other words it is highly contagious and can cause life threats if unattended. COVID-19 is a virus, and hence antibody treatment is not feasible or sufficient in this case. Being a novel strain, the success in finding out a possible treatment is still keeping the scientists and medical practitioners on their toes. The most effective ways to protect the body are to frequently clean the hands, cover the cough with the bend of elbow or tissue, and maintain a distance of at least 1 meter (3 feet) from people who are coughing or sneezing or wear protective mask covering nose and mouth. Lots of research papers have been published on this very sensitive issue, but these publications still leave a gap to cover the impact of this unknown tiny entity on different sectors of human civilization. COVID-19 is expected to seriously scratch the world economic profile. The global economy could shrink by up to 1 per cent in 2020 due to the corona virus pandemic, a reversal from the previous forecast of 2.5 per cent growth.
With reference to this question, there is a probability of 1 in transmission by this method.
Abhijit Mitra ,
Thank you so much; I greatly appreciate your expert answer, " . . . With reference to this question, there is a probability of 1 in transmission by this method."
As an admirer of your scientific research and professorial leadership in directing at least thirty-nine post-graduate students to Ph.D. status, I am most grateful for your contribution to this ResearchGate discussion pertaining to the transmission of the corona virus, which has, as you say, caused "the global economy" to "shrink by up to 1 per cent in 2020," which is "a reversal from the previous forecast of 2.5 per cent growth."
With my best regards.
Sweating can help in spreading the Coronavirus SARS 2 but only indirectly. For the detailed discussion of the plausible mechanisms please consult a popular paper: "Sweating Can Help Spread Covid-19, But Not By ‘Infectious Sweat’
https://www.forbes.com/sites/jvchamary/2020/09/29/coronavirus-infectious-sweat/?sh=755a17422a85
Janusz Pudykiewicz ,
Thank you for your answer and also the Forbes LINK, in which perhaps the most important point is made, as follows:
"Sweating can help spread Covid-19. That's not because virus-laden 'infectious sweat' might drip onto surfaces, but because sweating will bring your hands into contact with the droplets released from your respiratory tract — and if you're uninfected, that region is also where a coronavirus can gain entry to your body.
Simply put, Coronavirus is spread indirectly as a consequence of sweating. When you wipe the sweat from your brow during physical activity such as exercise or manual labour, you touch the area where respiratory droplets are most commonly found, a 'T-zone' around your eyes and nose, mouth and chin.
You might transfer virus particles from your face to an object like a door handle or free weights. Unless they're cleaned with disinfectant, another person might then touch those contaminated surfaces and infect themselves after touching their own face.
Touching your face is hard to consciously control and happens without you even realising. A 2020 review by epidemiologists at the University of Auckland in New Zealand revealed that face-touching happens far more often than you might think: on average, people touch the T-zone almost 69 times per hour.
The implications of frequent face-touching during sweaty activities such as exercise are clear: you should be extra careful and get into habits like taking your own towel and sweatbands to the gym " (bold face print added for emphasis).
By JV Chamary
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JV Chamary (PhD, evolutionary biology) is a science communicator specialising in public engagement and outreach through entertainment, focusing on popular culture.