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| Coronavirus Infections May Not Be Uncommon, Tests Suggest | Coronavirus Infections May Not Be Uncommon, Tests Suggest |
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| Two new studies using antibody tests to assess how many people have been infected with the coronavirus have turned up numbers higher than some experts had expected. | Two new studies using antibody tests to assess how many people have been infected with the coronavirus have turned up numbers higher than some experts had expected. |
| Both studies were performed in California: one among residents of Santa Clara County, south of San Francisco, and the other among residents of Los Angeles County. In both cases, the estimates of the number of people infected in those counties were far higher than the number of confirmed cases. | Both studies were performed in California: one among residents of Santa Clara County, south of San Francisco, and the other among residents of Los Angeles County. In both cases, the estimates of the number of people infected in those counties were far higher than the number of confirmed cases. |
| The studies, conducted by public health officials and scientists at Stanford University and the University of Southern California, have earned the ire of critics who questioned both the recruitment methods and the analyses. | The studies, conducted by public health officials and scientists at Stanford University and the University of Southern California, have earned the ire of critics who questioned both the recruitment methods and the analyses. |
| In the Santa Clara County study, researchers tested 3,330 volunteers for antibodies indicating exposure to the virus. Roughly 1.5 percent were positive. | In the Santa Clara County study, researchers tested 3,330 volunteers for antibodies indicating exposure to the virus. Roughly 1.5 percent were positive. |
| After adjustments intended to account for differences between the sample and the population of the county as a whole, the researchers estimated that the prevalence of antibodies was between 2.5 percent and a bit more than 4 percent. The county’s population is 1.9 million. | After adjustments intended to account for differences between the sample and the population of the county as a whole, the researchers estimated that the prevalence of antibodies was between 2.5 percent and a bit more than 4 percent. The county’s population is 1.9 million. |
| That means that 48,000 to 81,000 people were infected with the coronavirus in Santa Clara County by early April, the investigators concluded. | That means that 48,000 to 81,000 people were infected with the coronavirus in Santa Clara County by early April, the investigators concluded. |
| In Los Angeles County, researchers conducted tests at drive-through sites and at participants’ homes and estimated that 2.8 percent to 5.6 percent of the county’s adult population carried antibodies to the coronavirus. There are 10.4 million people in Los Angeles County. | In Los Angeles County, researchers conducted tests at drive-through sites and at participants’ homes and estimated that 2.8 percent to 5.6 percent of the county’s adult population carried antibodies to the coronavirus. There are 10.4 million people in Los Angeles County. |
| If accurate, that would mean that 220,000 to 442,000 residents had been exposed. By comparison, only 8,000 cases had been confirmed in the county by early April, when the testing was done. | If accurate, that would mean that 220,000 to 442,000 residents had been exposed. By comparison, only 8,000 cases had been confirmed in the county by early April, when the testing was done. |
| While finding volunteers was not difficult, it’s not clear how representative they were of the populations at large. | While finding volunteers was not difficult, it’s not clear how representative they were of the populations at large. |
| To find participants in the Los Angeles County study, researchers used a random sample of email addresses and telephone numbers of residents to invite people to participate in what they said would be a Covid-19 survey. | To find participants in the Los Angeles County study, researchers used a random sample of email addresses and telephone numbers of residents to invite people to participate in what they said would be a Covid-19 survey. |
| The scientists set limits on participation, based on factors like ethnicity and age, in an effort to ensure the sample represented the county’s population. About 1,100 people signed up to be tested. | The scientists set limits on participation, based on factors like ethnicity and age, in an effort to ensure the sample represented the county’s population. About 1,100 people signed up to be tested. |
| The study in Santa Clara County found participants by advertising on Facebook. Most of the first volunteers were in wealthy ZIP codes, so the investigators also recruited from poorer areas. As in the Los Angeles County study, the goal was to get a representative sample of the population. | The study in Santa Clara County found participants by advertising on Facebook. Most of the first volunteers were in wealthy ZIP codes, so the investigators also recruited from poorer areas. As in the Los Angeles County study, the goal was to get a representative sample of the population. |
| “It’s not perfect, but it’s the best science can do,” said Dr. John Ioannidis, a professor of medicine at Stanford University and an author of the Santa Clara County report. | “It’s not perfect, but it’s the best science can do,” said Dr. John Ioannidis, a professor of medicine at Stanford University and an author of the Santa Clara County report. |
| Antibody studies in other countries have produced similar figures, he noted. | Antibody studies in other countries have produced similar figures, he noted. |
| If the numbers prove accurate, the coronavirus may be much less deadly than originally expected, with a fatality rate more closely resembling that of a seasonal flu strain than a pandemic of profound lethality. | If the numbers prove accurate, the coronavirus may be much less deadly than originally expected, with a fatality rate more closely resembling that of a seasonal flu strain than a pandemic of profound lethality. |
| But there are questions about who was tested. Among them: Were people who had reason to think they had been infected overrepresented among the volunteers? | But there are questions about who was tested. Among them: Were people who had reason to think they had been infected overrepresented among the volunteers? |
| “We tried to look into the possibility of bias influencing the results,” Dr. Ioannidis said. “We asked for symptoms recently and in the last few months, and were very careful with our adjustments. We did a very lengthy set of analyses.” | “We tried to look into the possibility of bias influencing the results,” Dr. Ioannidis said. “We asked for symptoms recently and in the last few months, and were very careful with our adjustments. We did a very lengthy set of analyses.” |
| That data will be published in a forthcoming appendix, he said. In any event, bias also can work to lower the numbers if the healthiest people were the ones inclined to be tested, a real possibility. | That data will be published in a forthcoming appendix, he said. In any event, bias also can work to lower the numbers if the healthiest people were the ones inclined to be tested, a real possibility. |
| “Nobody knows the truth — let’s be honest,” Dr. Ioannidis said of the prevalence figures. “But if I had to guess, I would say it is probably higher than our estimate.” | “Nobody knows the truth — let’s be honest,” Dr. Ioannidis said of the prevalence figures. “But if I had to guess, I would say it is probably higher than our estimate.” |
| Updated June 22, 2020 | |
| 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 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. | 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. | 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. | 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. |
| 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.) |
| 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. |
| Many widely available antibody tests have been found to be inaccurate. The investigators say they validated the accuracy of the tests they used beforehand, and argue that the tests could not be so much in error as to invalidate the conclusions. | Many widely available antibody tests have been found to be inaccurate. The investigators say they validated the accuracy of the tests they used beforehand, and argue that the tests could not be so much in error as to invalidate the conclusions. |
| For vulnerable people, like those in nursing homes, the virus obviously is a terrible threat. But the new data suggest most adults will experience milder to asymptomatic infections. | For vulnerable people, like those in nursing homes, the virus obviously is a terrible threat. But the new data suggest most adults will experience milder to asymptomatic infections. |
| “This is very consistent with the fact that the virus is very common but not killing at the rate we thought,” Dr. Ioannidis said. | “This is very consistent with the fact that the virus is very common but not killing at the rate we thought,” Dr. Ioannidis said. |
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| Little is known about the transmissibility of the virus by asymptomatic adults, however. That may complicate scientific understanding of the virus’s spread. | Little is known about the transmissibility of the virus by asymptomatic adults, however. That may complicate scientific understanding of the virus’s spread. |
| With better estimates of the virus’s prevalence and lethality, it may be easier to reopen society in a manner supported by data, said Neeraj Sood, vice dean of research at the University of Southern California Price School of Public Policy and an author of the Los Angeles County report. | With better estimates of the virus’s prevalence and lethality, it may be easier to reopen society in a manner supported by data, said Neeraj Sood, vice dean of research at the University of Southern California Price School of Public Policy and an author of the Los Angeles County report. |
| “We can model the scenarios,” he said. “We should not make decisions just based on I.C.U. mortality.” | “We can model the scenarios,” he said. “We should not make decisions just based on I.C.U. mortality.” |