Why disinfection is not a way to stop the coronavirus

Hong Kong — At Hong Kong’s deserted airports, cleaners constantly spray baggage carts, elevator buttons, and check-in counters with antibacterial fluid. In New York City, workers continuously disinfect the surfaces of buses and subways. In London, many pubs have spent a lot of money on intensive surface cleaning to reopen after the blockade — Before closing again in November..

Around the world, workers are soaping, wiping and fumigating their surfaces with an urgent sense of purpose to fight the coronavirus. However, scientists say there is little or no evidence that a contaminated surface can spread the virus. In crowded indoor spaces such as airports, viruses that are exhaled by infected people and stay in the air are a much greater threat, they say.

Hand wash with soap and water for 20 seconds — or disinfectant Without soap — it is advisable to stop the spread of the virus. However, rubbing the surface rarely reduces the threat of viruses indoors, and health officials are called upon to focus on improving ventilation and filtration of indoor air instead.

“In my opinion, surface disinfection wastes a lot of time, energy, and money, and more importantly, diverts attention and resources from preventing airborne transmission,” said a US respiratory infection. Expert Dr. Kevin P. Fennery said. National Institute of Health.

Some experts say that Hong Kong, a crowded city with a population of 7.5 million and a long history of infectious disease outbreaks, is a type of surgical surface cleaning that gives the general public a false sense of security about the coronavirus. It suggests that it is a case study.

The Airport Authority Hong Kong has split the airport staff in the quarantine area using a “whole body disinfection channel” like a telephone box. According to the airport, the booth is the first in the world and only staff are being used on a trial basis, and we are doing our utmost to make the facility a “safe environment for all users.”

Such exhibits can comfort the general public as they appear to show that local officials are fighting Covid-19. However, Sherry Miller, an aerosol expert at the University of Colorado at Boulder, said the booth had no practical implications from an infection control perspective.

The virus is released through the activity of spraying respiratory droplets (speaking, breathing, screaming, coughing, singing, sneezing). Also, disinfectant sprays are often made from toxic chemicals that can have a significant impact on indoor air quality and human health, Dr. Miller said.

“I don’t know why everyone thinks that disinfecting the whole person reduces the risk of getting a virus,” she said.

“Sanitary Theater”

Various respiratory illnesses, including the common cold and flu, are caused by bacteria that can spread from contaminated surfaces. Therefore, when the coronavirus outbreak occurred in mainland China last winter, it seemed reasonable to consider these so-called vectors as the primary means of spreading the pathogen.

Research soon discovered that the virus appeared to survive on several surfaces, including plastic and steel. Up to 3 days.. (Later studies have shown that many of these are likely dead fragments of non-infectious viruses.) The World Health Organization also emphasized surface infections as a risk to healthcare professionals. In certain medical procedures that produce aerosols, he said that airborne diffusion is a concern only if he is engaged.

However, there was increasing scientific evidence that the virus was possible. Stay in the air for hours Small droplets in stagnant air that infect people when inhaled — especially Crowded indoor space Ventilation is poor.

July essay Lancet Medical journals report coronavirus infections from the surface by some scientists without considering evidence from the work of closely related cousins, including SARS-CoV, the driving force behind the 2002-03 SARS epidemic. Claimed to exaggerate the risk of.

“This is very strong evidence that the transmission of vectors was at best minimal, at least with the original SARS virus,” said essay author Emmanuel Goldman, a microbiologist at Rutgers University. It is stated in. “There is no reason to expect the behavior of closely related SARS-CoV-2 to be significantly different in this type of experiment,” he added, referring to the new coronavirus.

A few days after Dr. Goldman’s Lancet essay was published, more than 200 scientists Called by WHO Acknowledge that the coronavirus can be spread by air in an indoor environment. Succumbing to public pressure on this issue, agencies have acknowledged that indoor aerosol infections can lead to outbreaks in poorly ventilated indoor areas such as restaurants, nightclubs, offices and places of worship.

By October, the Centers for Disease Control and Prevention, which had been maintained since May, will surface. “It’s not the main way the virus spreads“The transmission of infectious respiratory droplets is”Principal modeThrough it.

But by that time, the delusion of touching anything from railings to grocery bags had begun. And the instinct to scrub the surface as a precaution against Covid— “Sanitary theaterAs Atlantic magazine called it, “was already deeply rooted.

“My tennis partner and I gave up shaking hands at the end of the match — but what’s the point because I touched the tennis ball he touched?” Jeff Dier I wrote in my March essay For the New Yorker magazine, which captures the disgusting zeitgeist.

Don’t touch this

From Nairobi to Milan to Seoul, hazmat suit cleaners are fumigating public areas, despite WHO warning that chemicals can do more harm than good.

In Hong Kong, where 299 people died during the initial SARS epidemic, elevator buttons are often covered with plastic and cleaned multiple times a day. Some office building and subway crews wipe the escalator railings with disinfected rags as commuters climb. The cleaner blasted public places with antibacterial coatings and added a fleet of robots to clean the surface of subway cars.

Some Hong Kong-based scientists argue that deep cleaning does no harm, and the government’s strict social distance rules and the government’s months-long claim to wearing almost universal masks. Supported.

According to Procter & Gamble, sales of personal cleansing products increased by more than 30% in the quarter ending September, with double-digit growth in all regions of the world, including more than 20% in Greater China.

How about the air?

The burden of Covid-19 in Hong Kong (more than 5,400 confirmed cases and 108 deaths) is relatively low in any city. However, some experts say it is slow to address the risk of indoor aerosol infections.

Early on, authorities requested a restaurant in Hong Kong to install it. Partition between tables — Same kind Flimsy and essentially uselessThe protection used at the US Vice Presidential Debate in October.

However, as Hong Kong authorities are gradually relaxing restrictions on indoor meetings, a wedding ceremony There is concern that up to 50 people may have new outbreaks indoors.

Some experts say they are particularly concerned that coronavirus droplets can spread through office vents. Offices are crowded because the city has not yet developed a strong culture of remotework.

Professor Yeung King-lun of Chemistry and Biotechnology, Hong Kong University of Science and Technology, said: “People take off their masks at lunch or when they return to their private rooms because they assume their private room is their own private space.

“But remember, the air you breathe is basically a community.”

Mike Ives reported from Hong Kong and Apuorwa Mandabili from New York.