This article is from the source 'nytimes' and was first published or seen on . It last changed over 40 days ago and won't be checked again for changes.

You can find the current article at its original source at https://www.nytimes.com/2020/04/20/health/airflow-coronavirus-restaurants.html

The article has changed 28 times. There is an RSS feed of changes available.

Version 14 Version 15
How Coronavirus Infected Some, but Not All, in a Restaurant How Coronavirus Infected Some, but Not All, in a Restaurant
(1 day later)
In January, at a restaurant in Guangzhou, China, one diner infected with the novel coronavirus but not yet feeling sick appeared to have spread the disease to nine other people. One of the restaurant’s air-conditioners apparently blew the virus particles around the dining room.In January, at a restaurant in Guangzhou, China, one diner infected with the novel coronavirus but not yet feeling sick appeared to have spread the disease to nine other people. One of the restaurant’s air-conditioners apparently blew the virus particles around the dining room.
There were 73 other diners who ate that day on the same floor of the five-story restaurant, and the good news is they did not become sick. Neither did the eight employees who were working on the floor at the time.There were 73 other diners who ate that day on the same floor of the five-story restaurant, and the good news is they did not become sick. Neither did the eight employees who were working on the floor at the time.
Chinese researchers described the incident in a paper that is to be published in the July issue of the Emerging Infectious Diseases, a journal published by the Centers for Disease Control and Prevention. The field study has limitations. The researchers, for example, did not perform experiments to simulate the airborne transmission.Chinese researchers described the incident in a paper that is to be published in the July issue of the Emerging Infectious Diseases, a journal published by the Centers for Disease Control and Prevention. The field study has limitations. The researchers, for example, did not perform experiments to simulate the airborne transmission.
That outbreak illustrates some of the challenges that restaurants will face when they try to reopen. Ventilation systems can create complex patterns of airflow and keep viruses aloft, so simply spacing tables six feet apart — the minimum distance that the C.D.C. advises you keep from other people — may not be sufficient to safeguard restaurant patrons.That outbreak illustrates some of the challenges that restaurants will face when they try to reopen. Ventilation systems can create complex patterns of airflow and keep viruses aloft, so simply spacing tables six feet apart — the minimum distance that the C.D.C. advises you keep from other people — may not be sufficient to safeguard restaurant patrons.
The social nature of dining out could increase the risk. The longer people linger in a contaminated area, the more virus particles they would likely inhale. Eating is also one activity that cannot be accomplished while wearing a mask. Virus-laden droplets can be expelled into the air through breathing and talking, not just through coughs and sneezes.The social nature of dining out could increase the risk. The longer people linger in a contaminated area, the more virus particles they would likely inhale. Eating is also one activity that cannot be accomplished while wearing a mask. Virus-laden droplets can be expelled into the air through breathing and talking, not just through coughs and sneezes.
As the C.D.C. now advises, “Avoid large and small gatherings in private places and public spaces, such a friend’s house, parks, restaurants, shops, or any other place.”As the C.D.C. now advises, “Avoid large and small gatherings in private places and public spaces, such a friend’s house, parks, restaurants, shops, or any other place.”
On the other hand, all of the people who became sick at the restaurant in China were either at the same table as the infected person or at one of two neighboring tables. The fact that people farther away remained healthy is a hopeful hint that the coronavirus is primarily transmitted through larger respiratory droplets, which fall out of the air more quickly than smaller droplets known as aerosols, which can float for hours.On the other hand, all of the people who became sick at the restaurant in China were either at the same table as the infected person or at one of two neighboring tables. The fact that people farther away remained healthy is a hopeful hint that the coronavirus is primarily transmitted through larger respiratory droplets, which fall out of the air more quickly than smaller droplets known as aerosols, which can float for hours.
“I think it’s a well-done study with the limitations of being a field study,” said Werner E. Bischoff, the medical director of infection prevention and health system epidemiology at the Wake Forest School of Medicine in North Carolina. Dr. Bischoff was not involved with the research.“I think it’s a well-done study with the limitations of being a field study,” said Werner E. Bischoff, the medical director of infection prevention and health system epidemiology at the Wake Forest School of Medicine in North Carolina. Dr. Bischoff was not involved with the research.
On Jan. 24, a family went to lunch at the restaurant in Guangzhou, a sprawling metropolis in southern China located 80 miles from Hong Kong.On Jan. 24, a family went to lunch at the restaurant in Guangzhou, a sprawling metropolis in southern China located 80 miles from Hong Kong.
The family had left Wuhan, 520 miles to the north and the hot spot of the initial coronavirus outbreak, one day before Chinese officials imposed a lockdown on the city and the surrounding province of Hubei to slow the spread of the disease.The family had left Wuhan, 520 miles to the north and the hot spot of the initial coronavirus outbreak, one day before Chinese officials imposed a lockdown on the city and the surrounding province of Hubei to slow the spread of the disease.
At lunch, the five members of the family — designated Family A in the paper — appeared healthy. But later in the day, one of them, a 63-year-old woman, experienced a fever and a cough and went to the hospital where she tested positive for the coronavirus.At lunch, the five members of the family — designated Family A in the paper — appeared healthy. But later in the day, one of them, a 63-year-old woman, experienced a fever and a cough and went to the hospital where she tested positive for the coronavirus.
Within two weeks, nine others who ate lunch on that floor of the Guangzhou restaurant that day also tested positive. Four were relatives of the first infected woman. They could have been infected outside of the restaurant.Within two weeks, nine others who ate lunch on that floor of the Guangzhou restaurant that day also tested positive. Four were relatives of the first infected woman. They could have been infected outside of the restaurant.
But for the other five, the restaurant appears to have been the source of the virus.But for the other five, the restaurant appears to have been the source of the virus.
Family A’s table was on the west side of the 1,500-square foot dining room, between tables where two unrelated families, B and C, were also having lunch. Family B and Family A overlapped for a period of 53 minutes, and three of its members — a couple and their daughter — became sick. Family C sat next to Family A at the other neighboring table along the same side the room, overlapping for 73 minutes, and two of its members — a mother and her daughter — became ill.Family A’s table was on the west side of the 1,500-square foot dining room, between tables where two unrelated families, B and C, were also having lunch. Family B and Family A overlapped for a period of 53 minutes, and three of its members — a couple and their daughter — became sick. Family C sat next to Family A at the other neighboring table along the same side the room, overlapping for 73 minutes, and two of its members — a mother and her daughter — became ill.
Updated June 30, 2020
Common symptoms include fever, a dry cough, fatigue and difficulty breathing or shortness of breath. Some of these symptoms overlap with those of the flu, making detection difficult, but runny noses and stuffy sinuses are less common. The C.D.C. has also added chills, muscle pain, sore throat, headache and a new loss of the sense of taste or smell as symptoms to look out for. Most people fall ill five to seven days after exposure, but symptoms may appear in as few as two days or as many as 14 days.
Scientists around the country have tried to identify everyday materials that do a good job of filtering microscopic particles. In recent tests, HEPA furnace filters scored high, as did vacuum cleaner bags, fabric similar to flannel pajamas and those of 600-count pillowcases. Other materials tested included layered coffee filters and scarves and bandannas. These scored lower, but still captured a small percentage of particles.
A commentary published this month on the website of the British Journal of Sports Medicine points out that covering your face during exercise “comes with issues of potential breathing restriction and discomfort” and requires “balancing benefits versus possible adverse events.” Masks do alter exercise, says Cedric X. Bryant, the president and chief science officer of the American Council on Exercise, a nonprofit organization that funds exercise research and certifies fitness professionals. “In my personal experience,” he says, “heart rates are higher at the same relative intensity when you wear a mask.” Some people also could experience lightheadedness during familiar workouts while masked, says Len Kravitz, a professor of exercise science at the University of New Mexico.
The steroid, dexamethasone, is the first treatment shown to reduce mortality in severely ill patients, according to scientists in Britain. The drug appears to reduce inflammation caused by the immune system, protecting the tissues. In the study, dexamethasone reduced deaths of patients on ventilators by one-third, and deaths of patients on oxygen by one-fifth.
The coronavirus emergency relief package gives many American workers paid leave if they need to take time off because of the virus. It gives qualified workers two weeks of paid sick leave if they are ill, quarantined or seeking diagnosis or preventive care for coronavirus, or if they are caring for sick family members. It gives 12 weeks of paid leave to people caring for children whose schools are closed or whose child care provider is unavailable because of the coronavirus. It is the first time the United States has had widespread federally mandated paid leave, and includes people who don’t typically get such benefits, like part-time and gig economy workers. But the measure excludes at least half of private-sector workers, including those at the country’s largest employers, and gives small employers significant leeway to deny leave.
So far, the evidence seems to show it does. A widely cited paper published in April suggests that people are most infectious about two days before the onset of coronavirus symptoms and estimated that 44 percent of new infections were a result of transmission from people who were not yet showing symptoms. Recently, a top expert at the World Health Organization stated that transmission of the coronavirus by people who did not have symptoms was “very rare,” but she later walked back that statement.
Touching contaminated objects and then infecting ourselves with the germs is not typically how the virus spreads. But it can happen. A number of studies of flu, rhinovirus, coronavirus and other microbes have shown that respiratory illnesses, including the new coronavirus, can spread by touching contaminated surfaces, particularly in places like day care centers, offices and hospitals. But a long chain of events has to happen for the disease to spread that way. The best way to protect yourself from coronavirus — whether it’s surface transmission or close human contact — is still social distancing, washing your hands, not touching your face and wearing masks.
A study by European scientists is the first to document a strong statistical link between genetic variations and Covid-19, the illness caused by the coronavirus. Having Type A blood was linked to a 50 percent increase in the likelihood that a patient would need to get oxygen or to go on a ventilator, according to the new study.
The unemployment rate fell to 13.3 percent in May, the Labor Department said on June 5, an unexpected improvement in the nation’s job market as hiring rebounded faster than economists expected. Economists had forecast the unemployment rate to increase to as much as 20 percent, after it hit 14.7 percent in April, which was the highest since the government began keeping official statistics after World War II. But the unemployment rate dipped instead, with employers adding 2.5 million jobs, after more than 20 million jobs were lost in April.
If air travel is unavoidable, there are some steps you can take to protect yourself. Most important: Wash your hands often, and stop touching your face. If possible, choose a window seat. A study from Emory University found that during flu season, the safest place to sit on a plane is by a window, as people sitting in window seats had less contact with potentially sick people. Disinfect hard surfaces. When you get to your seat and your hands are clean, use disinfecting wipes to clean the hard surfaces at your seat like the head and arm rest, the seatbelt buckle, the remote, screen, seat back pocket and the tray table. If the seat is hard and nonporous or leather or pleather, you can wipe that down, too. (Using wipes on upholstered seats could lead to a wet seat and spreading of germs rather than killing them.)
If you’ve been exposed to the coronavirus or think you have, and have a fever or symptoms like a cough or difficulty breathing, call a doctor. They should give you advice on whether you should be tested, how to get tested, and how to seek medical treatment without potentially infecting or exposing others.
An air-conditioning unit next to Family C blew air in the southward direction across all three tables; some of the air likely bounced off the wall, back in the direction of Family C.An air-conditioning unit next to Family C blew air in the southward direction across all three tables; some of the air likely bounced off the wall, back in the direction of Family C.
Because the coronavirus had not yet spread widely beyond Wuhan, public health officials were able to trace the recent contacts of Families B and C and determine that the restaurant was the only likely place where they would have crossed paths with the virus.Because the coronavirus had not yet spread widely beyond Wuhan, public health officials were able to trace the recent contacts of Families B and C and determine that the restaurant was the only likely place where they would have crossed paths with the virus.
The researchers did not state in the paper whether any of the other diners who did not contract the coronavirus were members of the three affected families or if they were all customers at 12 other tables. The 73 people were quarantined for 14 days and did not develop symptoms.The researchers did not state in the paper whether any of the other diners who did not contract the coronavirus were members of the three affected families or if they were all customers at 12 other tables. The 73 people were quarantined for 14 days and did not develop symptoms.
“We conclude that in this outbreak, droplet transmission was prompted by air-conditioned ventilation,” the authors wrote. “The key factor for infection was the direction of the airflow.”“We conclude that in this outbreak, droplet transmission was prompted by air-conditioned ventilation,” the authors wrote. “The key factor for infection was the direction of the airflow.”
Harvey V. Fineberg, who leads the Standing Committee on Emerging Infectious Diseases and 21st Century Health Threats at the National Academies of Sciences, Engineering and Medicine, described the report as “provocative and eye-opening.”Harvey V. Fineberg, who leads the Standing Committee on Emerging Infectious Diseases and 21st Century Health Threats at the National Academies of Sciences, Engineering and Medicine, described the report as “provocative and eye-opening.”
He said restaurants should be mindful of the direction of airflow in arranging tables. Germicidal ultraviolet lights could also be installed to destroy floating virus particles, Dr. Fineberg said. And the paper’s findings could have implications beyond restaurants.He said restaurants should be mindful of the direction of airflow in arranging tables. Germicidal ultraviolet lights could also be installed to destroy floating virus particles, Dr. Fineberg said. And the paper’s findings could have implications beyond restaurants.
“It’s illuminating for the kind of thing we need to keep learning about as we try to configure safe work spaces,” Dr. Fineberg said. “Not just safe restaurant and entertainment venues but where you go to work.”“It’s illuminating for the kind of thing we need to keep learning about as we try to configure safe work spaces,” Dr. Fineberg said. “Not just safe restaurant and entertainment venues but where you go to work.”
[Like the Science Times page on Facebook. | Sign up for the Science Times newsletter.][Like the Science Times page on Facebook. | Sign up for the Science Times newsletter.]