Study Highlights Spread of COVID-19 Indoors: 5 Minute Exposure, 20 Feet Away, Still Infected | Photo credit: iStock Images
New Delhi / Seoul: Preventing the contraction of the new coronavirus, the virus that causes the COVID-19 disease, has been considered the best bet against the ongoing pandemic, especially since there is no specific treatment for the disease yet. Maintain social distancing: A distance of at least six feet from people in public spaces has been recommended to reduce the risk of contracting the infection. However, a recent study from South Korea has raised questions, after indoor COVID-19 transmission took place in just five minutes and with a distance of 20 feet between the carrier and the newly infected person.
It all started in June, when epidemiologist Dr. Lee Ju-hyung recreated conditions at a restaurant in Jeonju, a city in southwestern South Korea, where people dining inside contracted the new coronavirus from a visitor. from out of town. Among those who were infected with the virus was a high school student, who contracted the disease after just five minutes of exposure, more than 20 feet away.
The widely accepted standard of six feet of social distance may not be enough
The study was conducted by Lee and other epidemiologists. They also had the help of an engineer who specializes in aerodynamics. The results of the study were published last week in the Journal of Korean Medical Science. The study findings challenged the widely accepted standard of six feet of clearance that must be maintained to stop the spread of COVID-19.
The findings also add more value to the growing evidence of airborne transmission of the new coronavirus.
“In this outbreak, the distances between the contactor and infected people were … longer than the generally accepted 2 meters. [6.6-foot] droplet transmission range, ”the study authors wrote. “The guidelines on quarantine and epidemiological investigation must be updated to reflect these factors for the control and prevention of COVID-19,” reported the LA Times.
How the virus could have traveled more than 20 feet
Explaining how the new coronavirus may have traveled more than 20 feet, Linsey Marr, a professor of civil and environmental engineering at Virginia Tech who studies airborne virus transmission, said the five-minute window in which the student was infected It was because the drop was big enough to carry a viral load, but small enough to travel 20 feet in the air. Identifying the student in the study as A, he said, “A ‘had to receive a large dose in just five minutes, provided by larger aerosols, probably around 50 microns.
Large sprays or small droplets that overlap in the area close to the student can transmit disease over a meter or two (3.3 to 6.6 feet) if you have strong air flow.
How researchers discovered the possible spread of the new coronavirus in just 5 minutes, from 20 feet away
In reality, the study began with a mystery. A high school student in Jeonju tested positive for the virus on June 17. While it wouldn’t be as shocking anywhere else in the world at this time, the city had not seen a case of coronavirus in two months and thus this transmission seemed mysterious. . The province in which the city is located has not seen a case of COVID-19 in a month. Also, the girl who contracted the virus had not traveled anywhere in recent weeks. I had only been to school and back home.
Based on cell phone GPS data, the girl was found to have briefly overlapped with a COVID-19 patient from a different city and province. She was a door-to-door saleswoman who had visited the city. They had contacted on June 12, only for five minutes.
Study researcher Lee, who is also a professor at Jeonbuk National University School of Medicine, went to check out the restaurant and was surprised to see the CCTV footage of the day. These two people did not speak to each other and had been sitting far apart from each other the entire time. Interestingly, the two also didn’t touch any common surfaces like door handles, cups, or silverware. However, by the swinging of a lamp, Lee could tell that the restaurant’s air conditioning was on that day.
For more clarity, the team of researchers recreated the conditions. They sat at tables as substitutes and measured the air flow. They found that the student and another person who had been infected were sitting directly along with the flow of air from an air conditioner. Those who sat with their backs to the airflow were not infected. The researchers further found through genome sequencing that the virus genome types of the three patients also matched.
What we know about indoor transmission of COVID-19 so far
In July 2020, the WHO had recognized the possibility of airborne transmission of COVID-19. More than 200 researchers from around the world had said that there is undeniable evidence that viruses released by sneezing and coughing can remain floating in the air and also cause infections. The US Centers for Disease Control and Prevention also recognized the possibility of airborne transmission of the new coronavirus in October this year.
Other studies show similar findings: 23 bus passengers infected in China by a COVID-19 carrier
In addition to the study in question, several other studies have also found that the new coronavirus can be transmitted through the air and cause an infection. A study, published in JAMA Internal Medicine, also showed that 6 feet (2 meters) of distance may not be enough to prevent you from contracting coronavirus infection, especially in poorly ventilated spaces. The study found that a COVID-19 positive person infected at least 23 people who traveled with him on a bus to a religious event in less than two hours, in Zhejiang province, China.
A video recorded by American scientists also showed that drops from sneezing and coughing can travel farther than previously thought, raising concerns about the current norms of social distancing that people around the world follow.
The US CDC guidelines still say that a person is likely to contract COVID-19 only when they have been exposed to someone with the virus for more than 15 minutes, from less than 6 feet away.