We continue to clean the surfaces a lot because of the transmission of the SARS-CoV-2 coronavirus, as the World Health Organization (WHO) recommends. But what is the role of surfaces in the spread of the virus? Although it may have some impact, scientists have been suggesting that it is not a common way of spreading the virus. This coronavirus will be transmitted mainly by air, either by larger droplets or by smaller ones (aerosols).
What the WHO and the CDC say
In your latest updates on the way the virus is transmitted, the WHO says that “you can get infected by touching a contaminated surface and then moving your eyes, nose and mouth before washing your hands”. Therefore, it is recommended to disinfect surfaces that are touched very often. “Avoid touching surfaces, especially in public spaces, because someone with covid-19 may have touched them there before. Clean the surfaces regularly with the recommended disinfectants ”, read in site organization.
A WHO spokesman even told the site of the magazine Nature that “There is limited evidence of transmission through [objectos ou materiais que podem alojar um agente infeccioso e permitir a sua transmissão]. Even so, transmission through fomites is considered a possible form of transmission ”, due to the identification of SARS-CoV-2 RNA (genetic material) in the vicinity of infected people.
The United States Centers for Disease Control and Prevention (CDC) refer in your site that “we don’t think that [a propagação através das superfícies] be a common way for covid-19 to spread ”. But they warn that respiratory droplets can fall on surfaces and that people touch them. Thus, frequent disinfection of objects and surfaces that can be touched many times may be important, they advise.
What evidence is on the table
In March 2020, a study showed that SARS-CoV-2 could last on plastic and stainless steel for days. Another work released in April it also suggested that the virus remained infectious on solid surfaces, such as plastic, for six days. In the notes, it could last up to three days and in surgical masks, at least seven days. However, Emanuel Goldman (microbiologist at the Rutgers School of Medicine in New Jersey, USA) explained to Nature that the fact that the virus survives does not mean that people contract it on surfaces like handrails. In addition, he said that many of these studies have not tested this survival outside the laboratory.
In other investigations, viral RNA has been identified on the surfaces of medical facilities, personal effects or in water bottles. Initial studies suggested that this contamination could last for weeks. Emanuel Goldman again stressed that RNA contamination is not necessarily a cause for alarmism. “Viral RNA is the equivalent of the virus’s corpse. It is not infectious, ”he said. In fact, an investigation by a team at Assuta Ashdod University Hospital in Israel showed that in half of the samples from hospital objects it studied had viral RNA, as well as a third of the samples from hotel rooms where people quarantined them. But it was also seen that this viral RNA was not able to infect cells.
After further investigating this issue, Emanuel Goldman himself wrote in July a comment for the magazine The Lancet Infectious Diseases reporting that the surfaces presented a relatively small risk of coronavirus transmission. “In my opinion, the possibility of transmission through inanimate surfaces is very small, and only in circumstances where an infected person coughs or sneezes onto surfaces and someone then touches that surface right after,” he wrote. “I don’t disagree with the error for being too cautious, but this can lead to extremes that are not justified by the data.”
In December, Linsey Marr (researcher in the field of aerial disease transmission at Virginia Tech, USA) signed an opinion article in the newspaper The Washington Post in which he suggested that people slow down their cleaning efforts – where millions of euros are spent. “It became clear that aerosol inhalation transmission is an important form of transmission, if not the dominant one,” he said, quoted by Nature.
What should be done?
As for what to do, scientists say that it is necessary to continue investigating. Ben Cowling (epidemiologist at the University of Hong Kong) exemplified Nature that it is necessary to track well who infects who and which surfaces may be present at the time of transmission. “What would be really valuable was to do more epidemiological research on transmission patterns, whether in homes or workplaces. I don’t think we have done enough in this regard, ”he recommended. Ben Cowling also warned that, just because it has not been concluded that surfaces play a prominent role in SARS-CoV-2, it does not mean that the virus there cannot be contagious at some point.
Already in a hearing with other public health experts at the Eventual Commission for Monitoring the Application of Response Measures to Pandemic, Henrique Barros (president of the Public Health Institute of the University of Porto) also considered that the mechanisms for transmitting the disease should be better understood. infection and disease. “It is essential to understand what is going on,” he said. But, unlike the researchers heard by the Nature, referred that surfaces have been forgotten: “We know that there is no infection without people who transmit, we believe that too much emphasis has been placed on the transmission of people to people by air, forgetting the role of surfaces and it is necessary to review this position because part failure can also be out there. ”
In an editorial by Nature, it is even worth noting that, despite what scientists have been concluding, public health agencies continue to emphasize that surfaces are a threat and must be disinfected frequently. “The result is a confused public message”, it is considered. Therefore, the editorial warns that clearer guidelines are needed.
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