Covid-19: with the advancement of knowledge about the virus, is it useful to continue to disinfect everything?

MADRID.- The US administration has decided to fumigate the White House facilities after the March of Donald trump. So hours before Joe biden occupied the presidential residence, a team of agents devoted themselves to nebulize the disinfectant by the environments. Last week the British watched their Prime Minister, Boris Johnson, worked hard to clean the seat of a chair. One year after a novel coronavirus submissive to the world, too many measures are taken in front of the gallery. It’s him “Pandemic theater”, as defined in April 2020 by researcher Zeynep Tufekci in an article in which she criticized unnecessary or even counterproductive actions, such as the closure of parks.

In those first few weeks, the scientific evidence started to gather. Some, in a contradictory way. They scandalized the photographs of families in the gardens and walks, the safest places. Tables circulated on cellphones detailing how the coronavirus could withstand some surfaces. It was recommended to clean shoes, groceries and even clothes when returning from the street. But we’ve known for months that so much effort is not needed. “I stopped seeing compelling evidence a long time ago and I stopped doing it,” says virologist Margarita del Val of her determination to clean it up. The possibilities of contagion by surfaces – by vectors, in medical parlance – are rare. The European Center for Disease Control (ECDC) clarifies it as follows: “It is considered possible, although so far transmission by fomites has not been documented.” The CDC, its American equivalent, assures that “the spread by contact with contaminated surfaces is not considered a common form of the spread of COVID-19”.

After more than 100 million infections, it has not been possible to prove that a person has been infected after touching a contaminated surface. “After a year of the pandemic, the evidence is now clear. Coronavirus SARS-CoV-2 it is transmitted mainly through the air, by people speaking and exhaling large droplets and small particles called aerosols, ”the magazine concluded in an editorial. Nature. And he regretted that some authorities insist on permanent disinfection of surfaces: “The result is a confused public message when clear guidelines are needed on how to prioritize efforts to prevent the spread of the virus.” This does not mean that we stop washing our hands and using alcohol gel in stores, as direct contact is a possible route of infection. There is no need to concentrate efforts on disinfecting milk cartons or the walls of buildings that no one will touch.

Del Val, director of the CSIC platform for Covid, looks at the psychological aspect of the problem: “A lot of people have a maximum of a few steps in their daily life and one is the mask, the other cleans everything or distance and we also cannot ventilate ”. Elvis García, a public health expert at Harvard University, sees the problem with the “hygiene theater” that it “is easy to understand, intuitive and easy to attack.” And he adds: “The problem of particles and masks is more difficult to understand.” However, according to the Cosmo-Spain survey, from the Carlos III Health Institute, knowledge of the modes of contagion – and the need to ventilate – is high in Spain.

Already in its March 2020 recommendations, the ECDC advised cleaning only specially handled points, such as door handles, switches, handrails and elevator buttons, while on the streets the military already fumigated benches and outdoor sidewalks. Scientist Teresa Moreno, from IDAEA-CSIC, analyzed the presence of the coronavirus in the bars and buttons of the Barcelona metro and buses in the months of May and June. “At that time, people thought contagion was more caused by surfaces,” he recalls, but they also took air samples, because that’s their specialty. They found traces of the virus in both elements, but they were fragments that did not have the capacity to infect. “We found low levels in the air, and that was from when people weren’t wearing masks, so it didn’t appear to be a source of infection; I use public transport and don’t feel like I’m going to a dangerous place, ”says Moreno.

The most interesting thing is that there were vehicles that Transportes Metropolitanos de Barcelona cleaned with bleach and others by fumigating with ozone. Those that were disinfected with a rag and bleach were free of virus after cleaning, but not the sprayed buses. “We saw that with the ozone cannons, it was very difficult to spread throughout the vehicle. At low concentrations, ozone does nothing, we continued to find traces. And at very high levels, it is not viable because it is very toxic ”, indicates the scientist. “I am concerned about the gadgets that are being offered now because they are very toxic, they react with the materials and are harmful to health,” she warns. Del Val specifies: “It is not at all clear that they work, and you have to ventilate at the end anyway, because of the toxicity of the mucous membranes: well, ventilate well and that’s it.

The health authorities are clear in this regard. The ECDC notes that “the spraying (also called fumigation) of disinfectants outdoors or on large indoor surfaces (rooms, classrooms or buildings), or the use of ultraviolet rays, is not recommended for the population due to lack of efficacy, possible damage to the environment and possible exposure of humans to irritating chemicals ”. The World Health Organization (WHO) also clearly opposes the use of sprays, as unnecessary and dangerous, in environments and also in people, in those car washes that spray products when they enter certain environments.

On its page to dispel the myths of the pandemic, the WHO also specifies that the chances of contagion with shoes are “very low” and that the temperature scanners are not used to detect Covid patients, because many do not present this symptom and even so they are contagious. “The gun for measuring temperature doesn’t make much sense. In Ebola, yes, because you only infect if you have a fever, but in this case, the opportunity cost only concerns the gallery, ”García explains. And claims: “What you need are not thermometers for travelers, but a ten-day quarantine”. In addition, the ECDC the use of gloves is not recommended because “they do not confer any additional benefit and can lead to poor hand hygiene and greater contamination of surfaces”.

Again, these are theatrical decisions that can give a false sense of security, for someone entering a building with rugs to clean soles, spray arches, and assistants with thermometers. Harvard epidemiologist Miguel Hernán criticizes other “pandemic theaters” that continue to be performed, such as “the theater for imposing a safe distance, which is not controlled, in poorly ventilated bars like s’ there was no contagion from aerosols when speaking out loud because the music prevents hearing. “Or the” theater to recommend telecommuting instead of regulating it by law for all positions in which it is possible”.

García points to other questions which also seem to him to be representations without substance: “There are important measures which were not intended and things were invented in return, like pandemic hospitals, closures of perimeters while the ‘Incidence is just as high in all neighborhoods, discussions about curfews of places that should be closed, dressing astronauts for anything.’ “These are intuitive things, even if they don’t make sense,” he says. And he underlines one last aspect which has a great influence visually and psychologically: the waves of contagion. “It’s a construction that makes people predisposed to the arrival of the virus. Governments do well because we assume that something inevitable is happening. When we are faced with an epidemic, we have to go deep to end it, not to use this theatrical language of the waves, ”he criticizes.

© EL PAÍS, SL.

THE COUNTRY

More information