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| Is It Safe to Come Out of Lockdown? Check the Sewer | Is It Safe to Come Out of Lockdown? Check the Sewer |
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| The world is eager to come out of lockdown. But if countries simply return to business as usual, new outbreaks of Covid-19 will follow. The only solution that public health experts see is to keep careful track of the coronavirus and clamp down on new flare-ups. | The world is eager to come out of lockdown. But if countries simply return to business as usual, new outbreaks of Covid-19 will follow. The only solution that public health experts see is to keep careful track of the coronavirus and clamp down on new flare-ups. |
| The trouble is that the most obvious way to monitor the virus — testing person by person — has already proved to be a huge, expensive challenge. Experts say we’re nowhere near the scale we need to get a good picture of the pandemic. | The trouble is that the most obvious way to monitor the virus — testing person by person — has already proved to be a huge, expensive challenge. Experts say we’re nowhere near the scale we need to get a good picture of the pandemic. |
| Now some scientists are looking for the virus not in our noses, blood or spit, but somewhere else: in our sewers. | Now some scientists are looking for the virus not in our noses, blood or spit, but somewhere else: in our sewers. |
| “It’s the signature of a whole community,” said Krista Wigginton, an environmental engineer at the University of Michigan who has been finding the coronavirus in wastewater around the Bay Area in California. | “It’s the signature of a whole community,” said Krista Wigginton, an environmental engineer at the University of Michigan who has been finding the coronavirus in wastewater around the Bay Area in California. |
| Water authorities and governments are in discussions with scientists and companies about tracking the pandemic through the detection of viruses in the sewer. Wastewater monitoring could provide early warnings of outbreaks. It could potentially give governments some of the data they need about when to end lockdowns and when to ratchet them back up. | Water authorities and governments are in discussions with scientists and companies about tracking the pandemic through the detection of viruses in the sewer. Wastewater monitoring could provide early warnings of outbreaks. It could potentially give governments some of the data they need about when to end lockdowns and when to ratchet them back up. |
| Measuring viruses in wastewater in effect tests an entire city or region at once. While only some people may get tested for the coronavirus on a given day, everyone uses the toilet. | Measuring viruses in wastewater in effect tests an entire city or region at once. While only some people may get tested for the coronavirus on a given day, everyone uses the toilet. |
| “It’s a great leveler,” said Christobel Ferguson, chief innovation officer of the Water Research Foundation. | “It’s a great leveler,” said Christobel Ferguson, chief innovation officer of the Water Research Foundation. |
| This week, the foundation sponsored a virtual research summit, during which Dr. Wigginton and other experts shared their early results and developed a road map for improving their surveillance. | This week, the foundation sponsored a virtual research summit, during which Dr. Wigginton and other experts shared their early results and developed a road map for improving their surveillance. |
| For decades, public health workers have looked in sewage for signs of viral outbreaks. The World Health Organization has monitored polio viruses this way, to assess how well its vaccination campaigns have worked. | For decades, public health workers have looked in sewage for signs of viral outbreaks. The World Health Organization has monitored polio viruses this way, to assess how well its vaccination campaigns have worked. |
| In the early days, researchers had to run painstaking tests to find viruses in wastewater. They had to mix the water with cells so that the viruses could infect them. Then the researchers had to wait for the new viruses to emerge. | In the early days, researchers had to run painstaking tests to find viruses in wastewater. They had to mix the water with cells so that the viruses could infect them. Then the researchers had to wait for the new viruses to emerge. |
| Later, researchers were able to skip these experiments. They could simply fish out genetic material from the water, read its sequence, and determine what kind of virus they were dealing with. Even newer technology has made it possible to estimate the number of viruses by counting up the viral genes in a water sample. | Later, researchers were able to skip these experiments. They could simply fish out genetic material from the water, read its sequence, and determine what kind of virus they were dealing with. Even newer technology has made it possible to estimate the number of viruses by counting up the viral genes in a water sample. |
| Irene Xagoraraki, an environmental engineer at Michigan State University, uses this method to detect viruses in wastewater in Detroit. In a recent outbreak of hepatitis A, she found that the virus increased in the water about a week ahead of the rise in confirmed cases. “You can predict the outbreak,” she said. | Irene Xagoraraki, an environmental engineer at Michigan State University, uses this method to detect viruses in wastewater in Detroit. In a recent outbreak of hepatitis A, she found that the virus increased in the water about a week ahead of the rise in confirmed cases. “You can predict the outbreak,” she said. |
| When the coronavirus began spreading from China, Dr. Xagoraraki and other experts began wondering if they might see it turn up in wastewater. | When the coronavirus began spreading from China, Dr. Xagoraraki and other experts began wondering if they might see it turn up in wastewater. |
| The early reports about the coronavirus made the idea seemed plausible. Although the virus infects people’s airways first, it can eventually get into the intestines. | The early reports about the coronavirus made the idea seemed plausible. Although the virus infects people’s airways first, it can eventually get into the intestines. |
| The coronavirus has been detected in some infected people’s feces. Some early studies suggest that the virus becomes inactive by the time it gets to the sewer system. But it still carries genes that researchers can detect. | The coronavirus has been detected in some infected people’s feces. Some early studies suggest that the virus becomes inactive by the time it gets to the sewer system. But it still carries genes that researchers can detect. |
| “We started before the virus entered our country,” said Gertjan Medema of the KWR Water Research Institute in the Netherlands. He and his colleagues created a test for the coronavirus and began using it in wastewater in early February. | “We started before the virus entered our country,” said Gertjan Medema of the KWR Water Research Institute in the Netherlands. He and his colleagues created a test for the coronavirus and began using it in wastewater in early February. |
| They didn’t get any positive results, which was reassuring. They could be confident that their test was specific enough not to be fooled by other viruses. | They didn’t get any positive results, which was reassuring. They could be confident that their test was specific enough not to be fooled by other viruses. |
| After the Netherlands saw its first confirmed case on Feb. 27, Dr. Medema and his colleagues went back out to run more tests. They found the virus in the sewers of cities like Amsterdam and Utrecht. | After the Netherlands saw its first confirmed case on Feb. 27, Dr. Medema and his colleagues went back out to run more tests. They found the virus in the sewers of cities like Amsterdam and Utrecht. |
| The researchers then went to remote towns without any known cases of Covid-19. They discovered the coronavirus up to six days before the first confirmed cases were found there. | The researchers then went to remote towns without any known cases of Covid-19. They discovered the coronavirus up to six days before the first confirmed cases were found there. |
| Since then, Dr. Medema and his colleagues have continued to track the viruses in the sewer systems. As the confirmed cases of Covid-19 have gone up in Amsterdam and Utrecht, they have found more virus genes in the wastewater. | Since then, Dr. Medema and his colleagues have continued to track the viruses in the sewer systems. As the confirmed cases of Covid-19 have gone up in Amsterdam and Utrecht, they have found more virus genes in the wastewater. |
| Researchers have reported similar results from countries including Australia, France, Spain and the United States. | Researchers have reported similar results from countries including Australia, France, Spain and the United States. |
| Updated June 12, 2020 | Updated June 12, 2020 |
| 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. |
| 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. | 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. |
| 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. |
| At the meeting, the consensus of experts was that it’s not yet possible to use viruses in wastewater to estimate how many people are infected. | At the meeting, the consensus of experts was that it’s not yet possible to use viruses in wastewater to estimate how many people are infected. |
| For one thing, researchers are still trying to figure out the average number of viruses that infected people shed in their feces. For another, it’s not clear how many viral genes survive the journey from a toilet to a wastewater treatment plant. | For one thing, researchers are still trying to figure out the average number of viruses that infected people shed in their feces. For another, it’s not clear how many viral genes survive the journey from a toilet to a wastewater treatment plant. |
| “I don’t feel like we’re at a point where we can say, ‘This is the concentration in the wastewater and this is the number of people with illness,’” Dr. Wigginton said. | “I don’t feel like we’re at a point where we can say, ‘This is the concentration in the wastewater and this is the number of people with illness,’” Dr. Wigginton said. |
| Nevertheless, the experts who attended the meeting agreed that sewers have a lot to tell us about the pandemic. | Nevertheless, the experts who attended the meeting agreed that sewers have a lot to tell us about the pandemic. |
| The studies of Dr. Medema and others suggest that a weekly test of wastewater could serve as an early warning system for outbreaks. | The studies of Dr. Medema and others suggest that a weekly test of wastewater could serve as an early warning system for outbreaks. |
| When cities or states come out of lockdown, they could check the sewers to follow the virus trend. An increase would tell them that people were infecting each other. “Then you need to go back into quarantine,” said Eric Alm, a M.I.T. microbiologist and the scientific director of BioBot, a company that tracks pathogens in wastewater. | When cities or states come out of lockdown, they could check the sewers to follow the virus trend. An increase would tell them that people were infecting each other. “Then you need to go back into quarantine,” said Eric Alm, a M.I.T. microbiologist and the scientific director of BioBot, a company that tracks pathogens in wastewater. |
| Previous experience with other viruses has taught researchers to be careful about making sense of these apparent trends. If a huge crowd comes into a city to watch a football game, for example, the wastewater system may see a spike of viruses that has nothing to do with a new outbreak. | Previous experience with other viruses has taught researchers to be careful about making sense of these apparent trends. If a huge crowd comes into a city to watch a football game, for example, the wastewater system may see a spike of viruses that has nothing to do with a new outbreak. |
| “It requires good information,” Dr. Medema said, “but it’s a doable thing.” | “It requires good information,” Dr. Medema said, “but it’s a doable thing.” |
| As their testing becomes more reliable and precise, Dr. Medema and other researchers hope to zoom in on future outbreaks. Instead of looking at a wastewater treatment plant that handles an entire city or county, they may go down into manholes to monitor changes in individual neighborhoods. | As their testing becomes more reliable and precise, Dr. Medema and other researchers hope to zoom in on future outbreaks. Instead of looking at a wastewater treatment plant that handles an entire city or county, they may go down into manholes to monitor changes in individual neighborhoods. |
| Conceivably, they might be able to zero in on nursing homes, factories and other places that have seen intense outbreaks. | Conceivably, they might be able to zero in on nursing homes, factories and other places that have seen intense outbreaks. |
| “If we see a hot spot arising,” Dr. Xagoraraki said, “we can close down a particular area for a while, so you don’t kill the whole economy of a whole state.” | “If we see a hot spot arising,” Dr. Xagoraraki said, “we can close down a particular area for a while, so you don’t kill the whole economy of a whole state.” |
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