Updated: November 15, 2020 12:45:53 pm
While the virus that causes COVID-19, SARS-CoV-2, spreads through respiratory droplets from one person to another, it has been debated whether the droplets, including tiny aerosols, that contain the virus remain suspended. in the air for a long time. sufficient period of time.
When the researchers investigated the ventilation openings in one COVID-19 room and the central ducts that expel indoor air from three COVID-19 rooms, they were able to detect SARS-CoV-2 in the central ventilation systems, which were far from the areas of patients, which implies that the virus can be transported long distances. In the study, the authors note that this cannot be reasonably explained by droplet transmission alone and that airborne transmission of SARS-CoV-2 must be taken into account for preventive measures. Their findings were published in the journal Nature on November 11.
What is airborne transmission?
According to the WHO, airborne transmission is defined as the spread of an infectious agent caused by the spread of aerosols that remain infectious when suspended in the air over long distances and over time. Airborne transmission can occur during aerosol-generating medical procedures and even when speaking and singing.
What do we know about airborne transmission?
While the virus that causes COVID-19, SARS-CoV-2, spreads through respiratory droplets from one person to another, it has been debated whether the droplets, including tiny aerosols, that contain the virus remain suspended. in the air for a long time. enough time to allow the virus to infect a new person.
Amid the debate, the World Health Organization (WHO) has updated its guidelines. While WHO had already recognized that airborne transmission can occur during aerosol-generating medical procedures, the updated guidelines state that “WHO, together with the scientific community, has been actively discussing and evaluating whether SARS-CoV-2 it can also spread through aerosols in the absence of procedures that generate aerosols, particularly in indoor environments with poor ventilation ”.
In September, a study published on the JAMA Network suggested that airborne transmission on a bus in China caused an infected person to spread COVID-19 to more than 23 fellow travelers. In this study, the authors observed that among the cohort of individuals studied, those who traveled on Bus 2 had a higher risk of contracting the infection than those who did not, implying that the spread of COVID-19 in the air likely contributed to an increased risk of infection. attack rate on exposed bus. 📣 Express Explained is now on Telegram
Significantly, in May, the US Centers for Disease Control and Prevention (CDC) published a study titled “High Attack Rate of SARS-CoV-2 After Exposure in Choral Practice.” The researchers, who studied “super-propagation events,” found that after the 2.5-hour choir practice attended by 61 people, including a symptomatic index patient, 32 confirmed and 20 probable secondary cases of Covid-19 occurred; three patients were hospitalized and two died. Other such outbreaks have been reported in crowded indoor spaces, possibly via sprays in restaurants and fitness classes.
So what does the study say?
In their study, the researchers found RNA from the virus in the ventilation openings in operating rooms where COVID-19 patients were present. They also found viral RNA in fluid placed in open plates suspended below the vents, and similar levels of viral RNA were detected in leak filters and open Petri dishes.
Therefore, the study provides further evidence for the ability of SARS-CoV-2 to disperse from patients to room ventilation openings, as well as the detection of viral RNA in ventilation filters located at least 50 m ventilation openings in patient rooms.
The authors also point out that, although they could not conclude that the viral samples they studied conserved their infectious capacity, the distance at which they detected the RNA suggests that there may be some risk of airborne transmission, “especially at distances much closer to people. contagious in confined spaces, both inside and outside of hospital settings. “
© The Indian Express (P) Ltd
.
