“Disinfection Tunnels” Are Popping Up Around the World, Fueled By Misinformation and Fear
A screenshot of a video published by The Guardian of a tunnel used in a Mexican border town to "disinfect" U.S. visitors in an attempt to prevent them from spreading the coronavirus.
In an incident that sparked widespread outrage across India in late March, officials in the north Indian state of Uttar Pradesh sprayed hundreds of migrant workers, including women and children, with a chemical solution to sanitize them, in a misguided attempt to contain the spread of the novel coronavirus.
Since COVID-19 is a respiratory disorder, disinfecting a person's body or clothes cannot protect them from contracting the novel coronavirus, or help in containing the pathogen's spread.
Health officials reportedly doused the group with a diluted mixture of sodium hypochlorite – a bleaching agent harmful to humans, which led to complaints of skin rashes and eye irritation. The opposition termed the instance 'inhuman', compelling the state government to order an investigation into the mass 'chemical bath.'
"I don't think the officials thought this through," says Thomas Abraham, a professor with The University of Hong Kong, and a former consultant for the World Health Organisation (WHO) on risk communication. "Spraying people with bleach can prove to be harmful, and there is no guideline … that recommends it. This was some sort of a kneejerk reaction."
Although spraying individuals with chemicals led to a furor in the South Asian nation owing to its potential dangers, so-called "disinfection tunnels" have sprung up in crowded public places around the world, including malls, offices, airports, railway stations and markets. Touted as mass disinfectants, these tunnels spray individuals with chemical disinfectant liquids, mists or fumes through nozzles for a few seconds, purportedly to sanitize them -- though experts strongly condemn their use. The tunnels have appeared in at least 16 countries: India, Malaysia, Scotland, Albania, Argentina, Colombia, Singapore, China, Pakistan, France, Vietnam, Bosnia and Herzegovina, Chile, Mexico, Sri Lanka and Indonesia. Russian President Vladimir Putin even reportedly has his own tunnel at his residence.
While U.S. visitors to Mexico are "disinfected" through these sanitizing tunnels, there is no evidence that the mechanism is currently in use within the United States. However, the situation could rapidly change with international innovators like RD Pack, an Israeli start-up, pushing for their deployment. Many American and multinational companies like Stretch Structures, Guilio Barbieri and Inflatable Design Works are also producing these systems. As countries gradually ease lockdown restrictions, their demand is on the rise -- despite a stringent warning from the WHO against their potential health hazards.
"Spraying individuals with disinfectants (such as in a tunnel, cabinet, or chamber) is not recommended under any circumstances," the WHO warned in a report on May 15. "This could be physically and psychologically harmful and would not reduce an infected person's ability to spread the virus through droplets or contact. Moreover, spraying individuals with chlorine and other toxic chemicals could result in eye and skin irritation, bronchospasm due to inhalation, and gastrointestinal effects such as nausea and vomiting."
Disinfection tunnels largely spray a diluted mixture of sodium hypochlorite, a chlorine compound commonly known as bleach, often used to disinfect inanimate surfaces. Known for its hazardous properties, the WHO, in a separate advisory on COVID-19, warns that spraying bleach or any other disinfectant on individuals can prove to be poisonous if ingested, and that such substances should be used only to disinfect surfaces.
Considering the effect of sodium hypochlorite on mucous membranes, the European Centre for Disease Prevention and Control, an EU agency focussed on infectious diseases, recommends limited use of the chemical compound even when disinfecting surfaces – only 0.05 percent for cleaning surfaces, and 0.1 percent for toilets and bathroom sinks. The Indian health ministry also cautioned against spraying sodium hypochlorite recently, stating that its inhalation can lead to irritation of mucous membranes of the nose, throat, and respiratory tract.
In addition to the health hazards that such sterilizing systems pose, they have little utility, argues Indian virologist T. Jacob John. Since COVID-19 is a respiratory disorder, disinfecting a person's body or clothes cannot protect them from contracting the novel coronavirus, or help in containing the pathogen's spread.
"It's a respiratory infection, which means that you have the virus in your respiratory tract, and of course, that shows in your throat, therefore saliva, etc.," says John. "The virus does not survive outside the body for a long time, unless it is in freezing temperatures. Disinfecting a person's clothes or their body makes no sense."
Disinfection tunnels have limited, if any, impact on the main modes of coronavirus transmission, adds Craig Janes, director, School of Public Health and Health Systems at Canada's University of Waterloo. He explains that the nature of COVID-19 transmission is primarily from person-to-person, either directly, or via an object that is shared between two individuals. Measures like physical distancing and handwashing take care of these transmission risks.
"My view of these kinds of actions are that they are principally symbolic, indicating to a concerned population that 'something is being done,' to martial support for government or health system efforts," says Janes. "So perhaps a psychological benefit, but I'm not sure that this benefit would outweigh the risks."
"They may make people feel that their risk of infection has been reduced, and also that they do not have to worry about infecting others."
A recent report by Health Care Without Harm (HCWH), an international not-for-profit organization focused on sustainable health care around the world, states that disinfection tunnels have little evidence to demonstrate their efficacy or safety.
"If the goal is to reduce the spread of the virus by decontaminating the exterior clothing, shoes, and skin of the general public, there is no evidence that clothes are an important vector for transmission. If the goal is to attack the virus in the airways, what is the evidence that a 20-30 second external application is efficacious and safe?" the report questions. "The World Health Organization recommends more direct and effective ways to address hand hygiene, with interventions known to be effective."
If an infected person walks through a disinfection tunnel, he would still be infectious, as the chemicals will only disinfect the surfaces, says Gerald Keusch, a professor of medicine and international health at Boston University's Schools of Medicine and Public Health.
"While we know that viruses can be "disinfected" from surfaces and hands, disinfectants can be harmful to health if ingested or inhaled. The underlying principle of medicine is to do no harm, and we always measure benefit against risk when approving interventions. I don't know if this has been followed and assessed with respect to these devices," says Keusch. "It's a really bad idea."
Experts warn that such tunnels may also create a false sense of security, discouraging people from adopting best practice methods like handwashing, social distancing, avoiding crowded places, and using masks to combat the spread of COVID-19.
"They may make people feel that their risk of infection has been reduced, and also that they do not have to worry about infecting others," says Janes. "These are false assumptions, and may lead to increasing rather than reducing transmission."
In this week's Friday Five, an old diabetes drug finds an exciting new purpose. Plus, how to make the cities of the future less toxic, making old mice younger with EVs, a new reason for mysterious stillbirths - and much more.
The Friday Five covers five stories in research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.
Here is the promising research covered in this week's Friday Five:
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- How to make cities of the future less noisy
- An old diabetes drug could have a new purpose: treating an irregular heartbeat
- A new reason for mysterious stillbirths
- Making old mice younger with EVs
- No pain - or mucus - no gain
And an honorable mention this week: How treatments for depression can change the structure of the brain
Researchers at Stanford have found that the virus that causes Covid-19 can infect fat cells, which could help explain why obesity is linked to worse outcomes for those who catch Covid-19.
Obesity is a risk factor for worse outcomes for a variety of medical conditions ranging from cancer to Covid-19. Most experts attribute it simply to underlying low-grade inflammation and added weight that make breathing more difficult.
Now researchers have found a more direct reason: SARS-CoV-2, the virus that causes Covid-19, can infect adipocytes, more commonly known as fat cells, and macrophages, immune cells that are part of the broader matrix of cells that support fat tissue. Stanford University researchers Catherine Blish and Tracey McLaughlin are senior authors of the study.
Most of us think of fat as the spare tire that can accumulate around the middle as we age, but fat also is present closer to most internal organs. McLaughlin's research has focused on epicardial fat, “which sits right on top of the heart with no physical barrier at all,” she says. So if that fat got infected and inflamed, it might directly affect the heart.” That could help explain cardiovascular problems associated with Covid-19 infections.
Looking at tissue taken from autopsy, there was evidence of SARS-CoV-2 virus inside the fat cells as well as surrounding inflammation. In fat cells and immune cells harvested from health humans, infection in the laboratory drove "an inflammatory response, particularly in the macrophages…They secreted proteins that are typically seen in a cytokine storm” where the immune response runs amok with potential life-threatening consequences. This suggests to McLaughlin “that there could be a regional and even a systemic inflammatory response following infection in fat.”
It is easy to see how the airborne SARS-CoV-2 virus infects the nose and lungs, but how does it get into fat tissue? That is a mystery and the source of ample speculation.
The macrophages studied by McLaughlin and Blish were spewing out inflammatory proteins, While the the virus within them was replicating, the new viral particles were not able to replicate within those cells. It was a different story in the fat cells. “When [the virus] gets into the fat cells, it not only replicates, it's a productive infection, which means the resulting viral particles can infect another cell,” including microphages, McLaughlin explains. It seems to be a symbiotic tango of the virus between the two cell types that keeps the cycle going.
It is easy to see how the airborne SARS-CoV-2 virus infects the nose and lungs, but how does it get into fat tissue? That is a mystery and the source of ample speculation.
Macrophages are mobile; they engulf and carry invading pathogens to lymphoid tissue in the lymph nodes, tonsils and elsewhere in the body to alert T cells of the immune system to the pathogen. Perhaps some of them also carry the virus through the bloodstream to more distant tissue.
ACE2 receptors are the means by which SARS-CoV-2 latches on to and enters most cells. They are not thought to be common on fat cells, so initially most researchers thought it unlikely they would become infected.
However, while some cell receptors always sit on the surface of the cell, other receptors are expressed on the surface only under certain conditions. Philipp Scherer, a professor of internal medicine and director of the Touchstone Diabetes Center at the University of Texas Southwestern Medical Center, suggests that, in people who have obesity, “There might be higher levels of dysfunctional [fat cells] that facilitate entry of the virus,” either through transiently expressed ACE2 or other receptors. Inflammatory proteins generated by macrophages might contribute to this process.
Another hypothesis is that viral RNA might be smuggled into fat cells as cargo in small bits of material called extracellular vesicles, or EVs, that can travel between cells. Other researchers have shown that when EVs express ACE2 receptors, they can act as decoys for SARS-CoV-2, where the virus binds to them rather than a cell. These scientists are working to create drugs that mimic this decoy effect as an approach to therapy.
Do fat cells play a role in Long Covid? “Fat cells are a great place to hide. You have all the energy you need and fat cells turn over very slowly; they have a half-life of ten years,” says Scherer. Observational studies suggest that acute Covid-19 can trigger the onset of diabetes especially in people who are overweight, and that patients taking medicines to regulate their diabetes “were actually quite protective” against acute Covid-19. Scherer has funding to study the risks and benefits of those drugs in animal models of Long Covid.
McLaughlin says there are two areas of potential concern with fat tissue and Long Covid. One is that this tissue might serve as a “big reservoir where the virus continues to replicate and is sent out” to other parts of the body. The second is that inflammation due to infected fat cells and macrophages can result in fibrosis or scar tissue forming around organs, inhibiting their function. Once scar tissue forms, the tissue damage becomes more difficult to repair.
Current Covid-19 treatments work by stopping the virus from entering cells through the ACE2 receptor, so they likely would have no effect on virus that uses a different mechanism. That means another approach will have to be developed to complement the treatments we already have. So the best advice McLaughlin can offer today is to keep current on vaccinations and boosters and lose weight to reduce the risk associated with obesity.