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Stay 6 Feet Apart, We’re Told. But How Far Can Air Carry Coronavirus? Stay 6 Feet Apart, We’re Told. But How Far Can Air Carry Coronavirus?
(31 minutes later)
The rule of thumb, or rather feet, has been to stand six feet apart in public. That’s supposed to be a safe distance if a person nearby is coughing or sneezing and is infected with the novel coronavirus, spreading droplets that may carry virus particles.The rule of thumb, or rather feet, has been to stand six feet apart in public. That’s supposed to be a safe distance if a person nearby is coughing or sneezing and is infected with the novel coronavirus, spreading droplets that may carry virus particles.
And scientists agree that six feet is a sensible and useful minimum distance, but, some say, farther away would be better.And scientists agree that six feet is a sensible and useful minimum distance, but, some say, farther away would be better.
Six feet has never been a magic number that guarantees complete protection. The Centers for Disease Control and Prevention, one of the organizations using that measure, bases its recommendation on the idea that most large droplets that people expel when they cough or sneeze will fall to the ground within six feet.Six feet has never been a magic number that guarantees complete protection. The Centers for Disease Control and Prevention, one of the organizations using that measure, bases its recommendation on the idea that most large droplets that people expel when they cough or sneeze will fall to the ground within six feet.
But some scientists, having looked at studies of air flow and being concerned about smaller particles called aerosols, suggest that people consider a number of factors, including their own vulnerability and whether they are outdoors or in an enclosed room, when deciding whether six feet is enough distance.But some scientists, having looked at studies of air flow and being concerned about smaller particles called aerosols, suggest that people consider a number of factors, including their own vulnerability and whether they are outdoors or in an enclosed room, when deciding whether six feet is enough distance.
Sneezes, for instance, can launch droplets a lot farther than six feet according to a recent study.Sneezes, for instance, can launch droplets a lot farther than six feet according to a recent study.
No scientists are suggesting a wholesale change in behavior, or proposing that some other length for separation from another human, like seven, or nine feet, is actually the right one.No scientists are suggesting a wholesale change in behavior, or proposing that some other length for separation from another human, like seven, or nine feet, is actually the right one.
“Everything is about probability,” said Dr. Harvey Fineberg, who is the head of the Standing Committee on Emerging Infectious Diseases and 21st Century Health Threats at the National Academies of Sciences, Engineering and Medicine. “Three feet is better than nothing. Six feet is better than three feet. At that point, the larger drops have pretty much fallen down. Maybe if you’re out of spitting range, that could be even safer, but six feet is a pretty good number.”“Everything is about probability,” said Dr. Harvey Fineberg, who is the head of the Standing Committee on Emerging Infectious Diseases and 21st Century Health Threats at the National Academies of Sciences, Engineering and Medicine. “Three feet is better than nothing. Six feet is better than three feet. At that point, the larger drops have pretty much fallen down. Maybe if you’re out of spitting range, that could be even safer, but six feet is a pretty good number.”
One complicating factor is that aerosols, smaller droplets that can be emitted when people are breathing and talking, play some role in spreading the new coronavirus. Studies have shown that aerosols can be created during certain hospital or laboratory procedures like when using nebulizers to help patients inhale medication, which makes such procedures risky for doctors who do them.One complicating factor is that aerosols, smaller droplets that can be emitted when people are breathing and talking, play some role in spreading the new coronavirus. Studies have shown that aerosols can be created during certain hospital or laboratory procedures like when using nebulizers to help patients inhale medication, which makes such procedures risky for doctors who do them.
If the aerosols that people exhale in other settings are significant in spreading the disease, the six-foot distance would not be completely protective because those are carried more easily by air currents.If the aerosols that people exhale in other settings are significant in spreading the disease, the six-foot distance would not be completely protective because those are carried more easily by air currents.
Aerosols are generally considered to be particles under 5 microns in diameter, about the size of a red blood cell, and can be spread in the environment by talking and breathing. But some researchers argue that this is a false dichotomy. Infectious droplets can’t easily be divided into those that are big enough to fall to the ground quickly and those that stay aloft because so much depends on environmental conditions and how deeply they penetrate into the respiratory tract.Aerosols are generally considered to be particles under 5 microns in diameter, about the size of a red blood cell, and can be spread in the environment by talking and breathing. But some researchers argue that this is a false dichotomy. Infectious droplets can’t easily be divided into those that are big enough to fall to the ground quickly and those that stay aloft because so much depends on environmental conditions and how deeply they penetrate into the respiratory tract.
“It’s really a continuum,” said Dr. Donald Milton, who studies bioaerosols at the University of Maryland School of Public Health.“It’s really a continuum,” said Dr. Donald Milton, who studies bioaerosols at the University of Maryland School of Public Health.
Even without the launching power of a sneeze, air currents could carry a flow of aerosol sized virus particles exhaled by an infected person 20 feet or more away.Even without the launching power of a sneeze, air currents could carry a flow of aerosol sized virus particles exhaled by an infected person 20 feet or more away.
“In any confined geometry like an office room, meeting room, department store, food store,” said Eugene Chudnovsky, a physicist at Lehman College and the City University of New York’s Graduate Center. In a study not yet peer reviewed, he analyzed air flow and showed how, “the vortices in the air are taking the virus to different places.”“In any confined geometry like an office room, meeting room, department store, food store,” said Eugene Chudnovsky, a physicist at Lehman College and the City University of New York’s Graduate Center. In a study not yet peer reviewed, he analyzed air flow and showed how, “the vortices in the air are taking the virus to different places.”
A preliminary study at the University of Nebraska Medical Center found evidence of coronavirus genetic material on various surfaces in isolation rooms where infected patients were being treated, including on air vents more than six feet from the patients. The research, which has not yet been peer reviewed, indicates that the virus can occasionally travel long distances.A preliminary study at the University of Nebraska Medical Center found evidence of coronavirus genetic material on various surfaces in isolation rooms where infected patients were being treated, including on air vents more than six feet from the patients. The research, which has not yet been peer reviewed, indicates that the virus can occasionally travel long distances.
“The virus is so small, it can hitch a ride even on tiny, tiny particles,” Dr. Fineberg said. “But how important is each size and how well they can transmit disease is not fully understood.”“The virus is so small, it can hitch a ride even on tiny, tiny particles,” Dr. Fineberg said. “But how important is each size and how well they can transmit disease is not fully understood.”
It is also unclear how many virus particles it takes to start an infection, how long the viral particles remain viable or if studies like the one in Nebraska simply detected the genetic calling card the virus left behind.It is also unclear how many virus particles it takes to start an infection, how long the viral particles remain viable or if studies like the one in Nebraska simply detected the genetic calling card the virus left behind.
Spacing is an effective solution because it also reduces the number of people in a confined space. That reduces the likelihood of an infected person being in the group. And if there is one, fewer other people might be infected.Spacing is an effective solution because it also reduces the number of people in a confined space. That reduces the likelihood of an infected person being in the group. And if there is one, fewer other people might be infected.
Updated June 12, 2020Updated June 12, 2020
States are reopening bit by bit. This means that more public spaces are available for use and more and more businesses are being allowed to open again. The federal government is largely leaving the decision up to states, and some state leaders are leaving the decision up to local authorities. Even if you aren’t being told to stay at home, it’s still a good idea to limit trips outside and your interaction with other people. 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.
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.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.
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.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.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.
Mass protests against police brutality that have brought thousands of people onto the streets in cities across America are raising the specter of new coronavirus outbreaks, prompting political leaders, physicians and public health experts to warn that the crowds could cause a surge in cases. While many political leaders affirmed the right of protesters to express themselves, they urged the demonstrators to wear face masks and maintain social distancing, both to protect themselves and to prevent further community spread of the virus. Some infectious disease experts were reassured by the fact that the protests were held outdoors, saying the open air settings could mitigate the risk of transmission.Mass protests against police brutality that have brought thousands of people onto the streets in cities across America are raising the specter of new coronavirus outbreaks, prompting political leaders, physicians and public health experts to warn that the crowds could cause a surge in cases. While many political leaders affirmed the right of protesters to express themselves, they urged the demonstrators to wear face masks and maintain social distancing, both to protect themselves and to prevent further community spread of the virus. Some infectious disease experts were reassured by the fact that the protests were held outdoors, saying the open air settings could mitigate the risk of transmission.
Exercise researchers and physicians have some blunt advice for those of us aiming to return to regular exercise now: Start slowly and then rev up your workouts, also slowly. American adults tended to be about 12 percent less active after the stay-at-home mandates began in March than they were in January. But there are steps you can take to ease your way back into regular exercise safely. First, “start at no more than 50 percent of the exercise you were doing before Covid,” says Dr. Monica Rho, the chief of musculoskeletal medicine at the Shirley Ryan AbilityLab in Chicago. Thread in some preparatory squats, too, she advises. “When you haven’t been exercising, you lose muscle mass.” Expect some muscle twinges after these preliminary, post-lockdown sessions, especially a day or two later. But sudden or increasing pain during exercise is a clarion call to stop and return home.Exercise researchers and physicians have some blunt advice for those of us aiming to return to regular exercise now: Start slowly and then rev up your workouts, also slowly. American adults tended to be about 12 percent less active after the stay-at-home mandates began in March than they were in January. But there are steps you can take to ease your way back into regular exercise safely. First, “start at no more than 50 percent of the exercise you were doing before Covid,” says Dr. Monica Rho, the chief of musculoskeletal medicine at the Shirley Ryan AbilityLab in Chicago. Thread in some preparatory squats, too, she advises. “When you haven’t been exercising, you lose muscle mass.” Expect some muscle twinges after these preliminary, post-lockdown sessions, especially a day or two later. But sudden or increasing pain during exercise is a clarion call to stop and return home.
States are reopening bit by bit. This means that more public spaces are available for use and more and more businesses are being allowed to open again. The federal government is largely leaving the decision up to states, and some state leaders are leaving the decision up to local authorities. Even if you aren’t being told to stay at home, it’s still a good idea to limit trips outside and your interaction with other people.States are reopening bit by bit. This means that more public spaces are available for use and more and more businesses are being allowed to open again. The federal government is largely leaving the decision up to states, and some state leaders are leaving the decision up to local authorities. Even if you aren’t being told to stay at home, it’s still a good idea to limit trips outside and your interaction with other people.
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.
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.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.
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 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.)
Taking one’s temperature to look for signs of fever is not as easy as it sounds, as “normal” temperature numbers can vary, but generally, keep an eye out for a temperature of 100.5 degrees Fahrenheit or higher. If you don’t have a thermometer (they can be pricey these days), there are other ways to figure out if you have a fever, or are at risk of Covid-19 complications.Taking one’s temperature to look for signs of fever is not as easy as it sounds, as “normal” temperature numbers can vary, but generally, keep an eye out for a temperature of 100.5 degrees Fahrenheit or higher. If you don’t have a thermometer (they can be pricey these days), there are other ways to figure out if you have a fever, or are at risk of Covid-19 complications.
The C.D.C. has recommended that all Americans wear cloth masks if they go out in public. This is a shift in federal guidance reflecting new concerns that the coronavirus is being spread by infected people who have no symptoms. Until now, the C.D.C., like the W.H.O., has advised that ordinary people don’t need to wear masks unless they are sick and coughing. Part of the reason was to preserve medical-grade masks for health care workers who desperately need them at a time when they are in continuously short supply. Masks don’t replace hand washing and social distancing.The C.D.C. has recommended that all Americans wear cloth masks if they go out in public. This is a shift in federal guidance reflecting new concerns that the coronavirus is being spread by infected people who have no symptoms. Until now, the C.D.C., like the W.H.O., has advised that ordinary people don’t need to wear masks unless they are sick and coughing. Part of the reason was to preserve medical-grade masks for health care workers who desperately need them at a time when they are in continuously short supply. Masks don’t replace hand washing and social distancing.
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.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.
If you’re sick and you think you’ve been exposed to the new coronavirus, the C.D.C. recommends that you call your healthcare provider and explain your symptoms and fears. They will decide if you need to be tested. Keep in mind that there’s a chance — because of a lack of testing kits or because you’re asymptomatic, for instance — you won’t be able to get tested.If you’re sick and you think you’ve been exposed to the new coronavirus, the C.D.C. recommends that you call your healthcare provider and explain your symptoms and fears. They will decide if you need to be tested. Keep in mind that there’s a chance — because of a lack of testing kits or because you’re asymptomatic, for instance — you won’t be able to get tested.
Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said the six-foot distance would clearly “reduce the number of droplets you come in contact with. I have no doubt about that.”Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said the six-foot distance would clearly “reduce the number of droplets you come in contact with. I have no doubt about that.”
But, he said: “The question is what does it take for you to get infected? And that I think is the trillion-dollar question we have.”But, he said: “The question is what does it take for you to get infected? And that I think is the trillion-dollar question we have.”
He said, “Maybe all it takes is an aerosol. You don’t need any droplets at all.” If that’s the case, he said, then someone who is at high risk would not want to be in the same room with someone who is infected or might be infected.He said, “Maybe all it takes is an aerosol. You don’t need any droplets at all.” If that’s the case, he said, then someone who is at high risk would not want to be in the same room with someone who is infected or might be infected.
Current guidelines already suggest that anyone at high risk should stay home and not be out in public in the first place. And they seem to be working. Places where people reduced travel and started social distancing weeks ago, especially in California, New York and Washington, are starting to show a reduction in the number of new coronavirus cases.Current guidelines already suggest that anyone at high risk should stay home and not be out in public in the first place. And they seem to be working. Places where people reduced travel and started social distancing weeks ago, especially in California, New York and Washington, are starting to show a reduction in the number of new coronavirus cases.
People still need to shop and take care of necessities, Dr. Osterholm said, but reducing the risk of exposure to all possible modes of transmission — infected surfaces, droplets and smaller aerosols — is important.People still need to shop and take care of necessities, Dr. Osterholm said, but reducing the risk of exposure to all possible modes of transmission — infected surfaces, droplets and smaller aerosols — is important.
“Your job is to limit it as much as you can.”“Your job is to limit it as much as you can.”