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British researchers are now studying how long the coronavirus can survive in the air, writes The Guardian.
Researchers will test how long the virus remains contagious in different weather conditions and will try to answer a very essential question:
How long can the SARS-CoV-2 coronavirus survive in the tiny aerosol particles that we breathe out?
In a high-security laboratory near Bristol, researchers may now be only weeks away from finding out, writes The Guardian.
And they have developed a new machine that they believe will be adequate for the task, described in a study in the Journal of The Royal Society Interface in January 2019.
– Important question
On Monday, they begin to introduce drops of live Sars-CoV-2 and lift them up between two electrical rings to test how long the virus remains contagious under various environmental conditions.
– This is a very important question, says Professor Denis Doorly at Imperial College London to the British newspaper and adds:
– There is currently great interest in what is needed to reduce the risk of infection in closed rooms. It all depends on knowing how viable the virus remains in the air, says Doorly, who is not involved in the research.
Until now, covid-19 was expected to continue mainly through droplet infection, through respiratory droplets that are produced when an infected person coughs, sneezes, sings, speaks or breathes.
These drops quickly fall to the ground and represent the logic behind the 2 meter rule.
At the same time, there is a growing consensus among experts that the virus can appear in smaller droplets called aerosols, which can be carried greater distances by air currents and accumulate in poorly ventilated rooms.
Outbreak
This suspicion is largely based on outbreaks in restaurants and choirs, where people have been infected despite being at some distance from the carrier.
Genetic material of the virus has also been detected in air samples from poorly ventilated rooms, such as hospital bathrooms, but no one has yet identified live infectious viruses in air samples, says Professor Jonathan Reid of the University of Bristol, who leads the new research.
“We know that when bacteria or viruses are transmitted through the air in respiratory droplets, they dry out very quickly and can lose viability, so it is important to understand this when considering the role of airborne transmission in the transmission of COVID-19.” says Reid.
According to The Guardian, scientists have been using sealed containers, so-called Goldberg drums, for decades to investigate how long viruses can survive in aerosol droplets.
The virus is injected into the drum, which rotates to keep the droplets in the air, and samples are taken periodically for live viruses.
Using this method, American researchers have estimated that Sars-CoV-2 has an aerosol half-life of 1.1-1.2 hours, which means that half of the particles are out of the air after this time, and the infectious virus could still be detected later. three hours, when the experiment ended.
However, these calculations are imprecise due to the time it takes to inject the virus into the eardrum and the large amount of fluid that is used, which does not accurately reflect what happens when we cough or breathe.
New method
Therefore, Bristol researchers have developed devices that allow them to generate any number of small virus-containing particles, invisible to the naked eye, that float gently between two electrical rings for seconds, hours or days.
Ambient air temperature, humidity, and UV light intensity are strictly controlled and can be manipulated to recreate various real-world scenarios.
“We can effectively mimic a cold, wet British winter, or even a hot, dry summer in Saudi Arabia, to see how these dramatic differences in environmental conditions affect how long the virus remains contagious while in the air,” he said. Allen Haddrell, the University of Bristol chemist who designed and built the device, called Celebs, using 3D printers.
Coronaviruset tester
The team receives funding from Research and Innovation from the UK and the National Institute for Health Research.
The United States government has expressed an interest in the technology, to study other pathogens.
Until now, the team has practiced floating sprays that contain a mouse coronavirus, which is harmless to humans.
Here they have seen a big drop in infectivity during the first 10 minutes after virus release.
– We have also seen that this mouse virus at 10 degrees survives much longer than at warmer temperatures, says Haddrell.
On Monday, researchers will let the SARS-CoV-2 coronavirus rise for the first time, which means they may have the first results at the end of the week.
– They will be made available to decision makers and submitted for peer review in scientific journals, says Reid.
– Interesting and important
The National Institute of Public Health (NIPH) believes that research has something to offer.
– This is an interesting and important investigation. The big question, which has been difficult to clarify, is to what extent this airborne infection is of practical importance. There is fairly broad agreement that the most important mode of transmission is the transmission of droplets through the air over shorter distances, says director Atle Fretheim at FHI, adding:
“Even if you can find some live viruses that have traveled longer distances in the air, it doesn’t automatically mean that it carries a significant risk of infection,” says Fretheim.
Espen Rostrup Nakstad from the Norwegian Health Directorate is open to the fact that airborne infections can play a role in the spread of infection.
– When people sneeze, cough, yell or use a loud voice, small drops are spread with the air from the mouth and nose. These droplets can contain viruses and infectious bacteria when we have respiratory infections, says Dagbladet’s assistant director of health.
For most respiratory viruses, including SARS-CoV-2, large droplets will be the most contagious because they carry most of the virus particles. They also fall to the ground faster due to gravity and therefore do not spread as easily over distances greater than 1-2 meters.
– However, tiny droplets, so-called aerosols, can stay in the air longer before reaching the ground, and for the most contagious respiratory viruses out there, you can become infected if you enter a completely empty room where a person just stayed sick. Nakstad notes.
– It can be transmitted through an airborne infection.
He adds that for SARS-CoV-2 we still do not know how easy it is to become infected with aerosols.
– It depends on how long the virus “survives” in tiny droplets before it dries, and not least how many virus particles it has to be exposed to before becoming infected. Research that is currently available indicates that SARS-CoV-2 can be transmitted through aerosols, that is, airborne infections, but that droplet infection through close contact with sick people is the cause. most common infection, says Nakstad and elaborates:
– Airborne infections through aerosols possibly explain why so many people report being infected by asymptomatic people who do not cough or sneeze or feel sick. This is being mapped in ongoing studies.
Nakstad notes that the uncertainty associated with airborne infections is also the reason that hospitals use additional protection in so-called “aerosol-generating procedures”, which cause coughs and sneezes in infectious patients close to healthcare personnel.
– In most other patient situations, ordinary surgical dressings have been shown to protect well, and this supports the assumption that COVID-19 is primarily transmitted through normal contact and droplet infection. If you also follow normal infection control routines and stay away from sick people, you’ll be very well protected against infection in any case, Nakstad says.
