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Talking Can Generate Coronavirus Droplets That Linger Up to 14 Minutes Talking Can Generate Coronavirus Droplets That Linger Up to 14 Minutes
(about 13 hours later)
Coughs or sneezes may not be the only way people transmit infectious pathogens like the novel coronavirus to one another. Talking can also launch thousands of droplets so small they can remain suspended in the air for eight to 14 minutes, according to a new study.Coughs or sneezes may not be the only way people transmit infectious pathogens like the novel coronavirus to one another. Talking can also launch thousands of droplets so small they can remain suspended in the air for eight to 14 minutes, according to a new study.
The research, published Wednesday in The Proceedings of the National Academy of Sciences, could help explain how people with mild or no symptoms may infect others in close quarters such as offices, nursing homes, cruise ships and other confined spaces. The study’s experimental conditions will need to be replicated in more real-world circumstances, and researchers still don’t know how much virus has to be transmitted from one person to another to cause infection. But its findings strengthen the case for wearing masks and taking other precautions in such environments to reduce the spread of the coronavirus.The research, published Wednesday in The Proceedings of the National Academy of Sciences, could help explain how people with mild or no symptoms may infect others in close quarters such as offices, nursing homes, cruise ships and other confined spaces. The study’s experimental conditions will need to be replicated in more real-world circumstances, and researchers still don’t know how much virus has to be transmitted from one person to another to cause infection. But its findings strengthen the case for wearing masks and taking other precautions in such environments to reduce the spread of the coronavirus.
Scientists agree that the coronavirus jumps from person to person most often by hitching a ride inside tiny respiratory droplets. These droplets tend to fall to the ground within a few feet of the person who emits them. They may land on surfaces like doorknobs, where people can touch lingering virus particles and transfer them to their face. But some droplets can remain aloft, and be inhaled by others.Scientists agree that the coronavirus jumps from person to person most often by hitching a ride inside tiny respiratory droplets. These droplets tend to fall to the ground within a few feet of the person who emits them. They may land on surfaces like doorknobs, where people can touch lingering virus particles and transfer them to their face. But some droplets can remain aloft, and be inhaled by others.
Elaborate experiments have revealed how coughing or sneezing can produce a crackling burst of air mixed with saliva or mucus that can force hundreds of millions of influenza and other virus particles into the air if a person is sick. A single cough can propel about 3,000 respiratory droplets, while sneezing can generate as many as 40,000.Elaborate experiments have revealed how coughing or sneezing can produce a crackling burst of air mixed with saliva or mucus that can force hundreds of millions of influenza and other virus particles into the air if a person is sick. A single cough can propel about 3,000 respiratory droplets, while sneezing can generate as many as 40,000.
To see how many droplets are produced during normal conversation, researchers at the National Institute of Diabetes and Digestive and Kidney Diseases and the University of Pennsylvania, who study the kinetics of biological molecules inside the human body, asked volunteers to repeat the words “stay healthy” several times. While the participants spoke into the open end of a cardboard box, the researchers illuminated its inside with green lasers, and tracked bursts of droplets produced by the speaker.To see how many droplets are produced during normal conversation, researchers at the National Institute of Diabetes and Digestive and Kidney Diseases and the University of Pennsylvania, who study the kinetics of biological molecules inside the human body, asked volunteers to repeat the words “stay healthy” several times. While the participants spoke into the open end of a cardboard box, the researchers illuminated its inside with green lasers, and tracked bursts of droplets produced by the speaker.
The laser scans showed that about 2,600 small droplets were produced per second while talking. When researchers projected the amount and size of droplets produced at different volumes based on previous studies, they found that speaking louder could generate larger droplets, as well as greater quantities of them.The laser scans showed that about 2,600 small droplets were produced per second while talking. When researchers projected the amount and size of droplets produced at different volumes based on previous studies, they found that speaking louder could generate larger droplets, as well as greater quantities of them.
Although the scientists did not record speech droplets produced by people who were sick, previous studies have calculated exactly how much coronavirus genetic material can be found in oral fluids in the average patient. Based on this knowledge, the researchers estimated that a single minute of loud speaking could generate at least 1,000 virus-containing droplets.Although the scientists did not record speech droplets produced by people who were sick, previous studies have calculated exactly how much coronavirus genetic material can be found in oral fluids in the average patient. Based on this knowledge, the researchers estimated that a single minute of loud speaking could generate at least 1,000 virus-containing droplets.
The scientists also found that while droplets start shrinking from dehydration as soon as they leave a person’s mouth, they can still float in the air for eight to 14 minutes.The scientists also found that while droplets start shrinking from dehydration as soon as they leave a person’s mouth, they can still float in the air for eight to 14 minutes.
“These observations confirm that there is a substantial probability that normal speaking causes airborne virus transmission in confined environments,” the authors wrote in the study.“These observations confirm that there is a substantial probability that normal speaking causes airborne virus transmission in confined environments,” the authors wrote in the study.
The researchers acknowledged that the experiment was performed in a controlled environment with stagnant air that may not reflect what happens in rooms with good ventilation. But they still had reason to believe their reported values were “conservative lower limit estimates” because some people have a higher viral load, meaning they may produce droplets with several thousand more virus particles than average.The researchers acknowledged that the experiment was performed in a controlled environment with stagnant air that may not reflect what happens in rooms with good ventilation. But they still had reason to believe their reported values were “conservative lower limit estimates” because some people have a higher viral load, meaning they may produce droplets with several thousand more virus particles than average.
The Centers for Disease Control and Prevention says keeping at least six feet away from others can help people avoid contact with respiratory droplets and lower the risk of infection. But many scientists have argued that droplets can travel farther than six feet, depending on the force with which droplets are launched, the surrounding temperature, whether there are air currents that can carry them farther and other conditions.The Centers for Disease Control and Prevention says keeping at least six feet away from others can help people avoid contact with respiratory droplets and lower the risk of infection. But many scientists have argued that droplets can travel farther than six feet, depending on the force with which droplets are launched, the surrounding temperature, whether there are air currents that can carry them farther and other conditions.
There is also debate about whether the coronavirus can also be transmitted through even smaller droplets — less than a tenth the width of a human hair — that are known as aerosols, and can remain suspended or travel through the air for longer.There is also debate about whether the coronavirus can also be transmitted through even smaller droplets — less than a tenth the width of a human hair — that are known as aerosols, and can remain suspended or travel through the air for longer.
Updated May 28, 2020 Updated June 1, 2020
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.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.)
More than 40 million people — the equivalent of 1 in 4 U.S. workers — have filed for unemployment benefits since the pandemic took hold. One in five who were working in February reported losing a job or being furloughed in March or the beginning of April, data from a Federal Reserve survey released on May 14 showed, and that pain was highly concentrated among low earners. Fully 39 percent of former workers living in a household earning $40,000 or less lost work, compared with 13 percent in those making more than $100,000, a Fed official said.More than 40 million people — the equivalent of 1 in 4 U.S. workers — have filed for unemployment benefits since the pandemic took hold. One in five who were working in February reported losing a job or being furloughed in March or the beginning of April, data from a Federal Reserve survey released on May 14 showed, and that pain was highly concentrated among low earners. Fully 39 percent of former workers living in a household earning $40,000 or less lost work, compared with 13 percent in those making more than $100,000, a Fed official said.
There is an uptick in people reporting symptoms of chilblains, which are painful red or purple lesions that typically appear in the winter on fingers or toes. The lesions are emerging as yet another symptom of infection with the new coronavirus. Chilblains are caused by inflammation in small blood vessels in reaction to cold or damp conditions, but they are usually common in the coldest winter months. Federal health officials do not include toe lesions in the list of coronavirus symptoms, but some dermatologists are pushing for a change, saying so-called Covid toe should be sufficient grounds for testing.
Yes, but make sure you keep six feet of distance between you and people who don’t live in your home. Even if you just hang out in a park, rather than go for a jog or a walk, getting some fresh air, and hopefully sunshine, is a good idea.Yes, but make sure you keep six feet of distance between you and people who don’t live in your home. Even if you just hang out in a park, rather than go for a jog or a walk, getting some fresh air, and hopefully sunshine, is a good idea.
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.
Charity Navigator, which evaluates charities using a numbers-based system, has a running list of nonprofits working in communities affected by the outbreak. You can give blood through the American Red Cross, and World Central Kitchen has stepped in to distribute meals in major cities.Charity Navigator, which evaluates charities using a numbers-based system, has a running list of nonprofits working in communities affected by the outbreak. You can give blood through the American Red Cross, and World Central Kitchen has stepped in to distribute meals in major cities.
In another recent study, the same authors showed that just articulating certain sounds can produce significantly higher amounts of respiratory particles. The “th” sound in the word “healthy,” for example, was a very efficient generator of speech droplets. Another paper, published in January by researchers from the University of California, Davis, found the vowel sound “e” in “need” produces more droplets than the “a” in “saw,” or “o” in “mood.”In another recent study, the same authors showed that just articulating certain sounds can produce significantly higher amounts of respiratory particles. The “th” sound in the word “healthy,” for example, was a very efficient generator of speech droplets. Another paper, published in January by researchers from the University of California, Davis, found the vowel sound “e” in “need” produces more droplets than the “a” in “saw,” or “o” in “mood.”
What researchers don’t yet know is whether all speech, cough and sneeze droplets carrying virus particles are equally infectious, or if a specific amount of virus needs to be transmitted for a person to get sick by breathing it in.What researchers don’t yet know is whether all speech, cough and sneeze droplets carrying virus particles are equally infectious, or if a specific amount of virus needs to be transmitted for a person to get sick by breathing it in.
But the new study adds to the case for maintaining a physical distance from other people to help slow the spread of coronavirus, said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech who was not involved with the paper.But the new study adds to the case for maintaining a physical distance from other people to help slow the spread of coronavirus, said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech who was not involved with the paper.
“Based on this and other evidence, it would be wise to avoid extended face-to-face conversations with other people unless you are far apart and in a well-ventilated space, including outdoors,” Dr. Marr said.“Based on this and other evidence, it would be wise to avoid extended face-to-face conversations with other people unless you are far apart and in a well-ventilated space, including outdoors,” Dr. Marr said.
The study also highlights the importance of wearing masks during social and other interactions.The study also highlights the importance of wearing masks during social and other interactions.
“The risk of talking to one another will probably be lower than being exposed to a person who is not wearing a mask and openly coughs and sneezes,” said Dr. Werner E. Bischoff, the medical director of infection prevention and health system epidemiology at the Wake Forest School of Medicine. “Normal talking to a person while keeping the recommended social distance will be fine. Putting on a mask will be even better.”“The risk of talking to one another will probably be lower than being exposed to a person who is not wearing a mask and openly coughs and sneezes,” said Dr. Werner E. Bischoff, the medical director of infection prevention and health system epidemiology at the Wake Forest School of Medicine. “Normal talking to a person while keeping the recommended social distance will be fine. Putting on a mask will be even better.”