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After 6 Months, Important Mysteries About Coronavirus Endure | After 6 Months, Important Mysteries About Coronavirus Endure |
(7 days later) | |
[Follow our live coronavirus pandemic updates.] | [Follow our live coronavirus pandemic updates.] |
In the time since the world’s scientists and public health officials first became widely aware of the new coronavirus in January, they’ve had six months to learn about it. | In the time since the world’s scientists and public health officials first became widely aware of the new coronavirus in January, they’ve had six months to learn about it. |
They’ve reached many conclusions about the virus and the illness it causes, from the importance of wearing masks to contain it, to the unusual range of symptoms it provokes. | They’ve reached many conclusions about the virus and the illness it causes, from the importance of wearing masks to contain it, to the unusual range of symptoms it provokes. |
But there are major gaps in scientific knowledge about the virus. In the half year that journalists of the health and science desk of The Times have been reporting on Sars-CoV-2, we have identified some of the enduring uncertainties. How scientists resolve some of these mysteries will shape our future with the coronavirus. | But there are major gaps in scientific knowledge about the virus. In the half year that journalists of the health and science desk of The Times have been reporting on Sars-CoV-2, we have identified some of the enduring uncertainties. How scientists resolve some of these mysteries will shape our future with the coronavirus. |
By Donald G. McNeil Jr. | By Donald G. McNeil Jr. |
One of the epidemic’s great unknowns is how many Americans have been infected so far. | One of the epidemic’s great unknowns is how many Americans have been infected so far. |
Only about 1.9 million Americans had tested positive as of May 28, according to the Centers for Disease Control and Prevention — or perhaps only about 1.7 million according to the Johns Hopkins Center for Health Security, which produces a frequently cited map of world cases. | Only about 1.9 million Americans had tested positive as of May 28, according to the Centers for Disease Control and Prevention — or perhaps only about 1.7 million according to the Johns Hopkins Center for Health Security, which produces a frequently cited map of world cases. |
Statisticians believe the actual number of cases is higher, but it is not clear by how much. | Statisticians believe the actual number of cases is higher, but it is not clear by how much. |
They have more confidence in the accuracy of data produced by states that do the most testing. On that score, New York is a leader; it has tested about 9.6 percent of its population, which is almost double the national average. (Rhode Island tested 13 percent of its people, beating New York, but its population is small.) | They have more confidence in the accuracy of data produced by states that do the most testing. On that score, New York is a leader; it has tested about 9.6 percent of its population, which is almost double the national average. (Rhode Island tested 13 percent of its people, beating New York, but its population is small.) |
New York has also done tens of thousands of antibody tests for surveillance purposes. On May 22, Gov. Andrew Cuomo announced that, according to these tests, about a fifth of all New York City residents have had the virus, as had about 27 percent of thousands of black and Hispanic New Yorkers who were tested at their local churches. | New York has also done tens of thousands of antibody tests for surveillance purposes. On May 22, Gov. Andrew Cuomo announced that, according to these tests, about a fifth of all New York City residents have had the virus, as had about 27 percent of thousands of black and Hispanic New Yorkers who were tested at their local churches. |
If that same pattern were assumed to hold in other hard-hit big cities like Chicago, New Orleans, Detroit and Miami, it is likely that somewhere between 3 and 4 million urban Americans were infected. | If that same pattern were assumed to hold in other hard-hit big cities like Chicago, New Orleans, Detroit and Miami, it is likely that somewhere between 3 and 4 million urban Americans were infected. |
Even if that figure was doubled or tripled — which is probably generous — to account for Americans infected all around the country before the lockdowns, that would still be only 9 to 12 million people. | Even if that figure was doubled or tripled — which is probably generous — to account for Americans infected all around the country before the lockdowns, that would still be only 9 to 12 million people. |
That is in line with the low end of estimates made in mid-April, before antibody testing began; different modelers predicted then that between 3 and 10 percent of the country was infected. | That is in line with the low end of estimates made in mid-April, before antibody testing began; different modelers predicted then that between 3 and 10 percent of the country was infected. |
In any case, since this is a country of 330 million, a mere 10 million or even 20 million infected would be a drop in the bucket. As the country comes out of lockdown, the vast majority of Americans remain vulnerable to the virus. | In any case, since this is a country of 330 million, a mere 10 million or even 20 million infected would be a drop in the bucket. As the country comes out of lockdown, the vast majority of Americans remain vulnerable to the virus. |
Nor will the country be able to spot all of those who get it. The C.D.C.’s “best estimate,” according to the pandemic scenarios it issued May 22, is that about 35 percent of those infected have no symptoms. | Nor will the country be able to spot all of those who get it. The C.D.C.’s “best estimate,” according to the pandemic scenarios it issued May 22, is that about 35 percent of those infected have no symptoms. |
Currently, about 21,000 Americans are getting infected each day. If a third of them show no symptoms, almost 210,000 “silent spreaders” are created each month. | Currently, about 21,000 Americans are getting infected each day. If a third of them show no symptoms, almost 210,000 “silent spreaders” are created each month. |
It seems impossible to imagine that any contact-tracing program, no matter how large, will be able to keep up with that. | It seems impossible to imagine that any contact-tracing program, no matter how large, will be able to keep up with that. |
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By Apoorva Mandavilli | By Apoorva Mandavilli |
Here’s what we can say for sure about the minimum number of viral particles it takes to seed a coronavirus infection: The number is somewhere between one and one million. | Here’s what we can say for sure about the minimum number of viral particles it takes to seed a coronavirus infection: The number is somewhere between one and one million. |
If you push scientists harder, they might offer a slightly smaller range of a few hundred to a few thousand — and some might even bravely throw out an estimate in the high hundreds, based on what they have learned about the behavior of the coronavirus that caused the 2002-03 SARS epidemic. | If you push scientists harder, they might offer a slightly smaller range of a few hundred to a few thousand — and some might even bravely throw out an estimate in the high hundreds, based on what they have learned about the behavior of the coronavirus that caused the 2002-03 SARS epidemic. |
But the bottom line is that no one will know for sure until more research is completed. | But the bottom line is that no one will know for sure until more research is completed. |
“It’s very unsatisfying to tell people, ‘Oh we don’t know,’” said Angela Rasmussen, a virologist at Columbia University in New York. “People do have a lot of questions about this.” | “It’s very unsatisfying to tell people, ‘Oh we don’t know,’” said Angela Rasmussen, a virologist at Columbia University in New York. “People do have a lot of questions about this.” |
It’s difficult to say anything definitive about the coronavirus because it behaves like an influenza virus in how easily it is transmitted, and in that people can pass it on even when they don’t seem sick. But its structure, origin in bats and overall symptoms are similar to those of its cousin coronaviruses. | It’s difficult to say anything definitive about the coronavirus because it behaves like an influenza virus in how easily it is transmitted, and in that people can pass it on even when they don’t seem sick. But its structure, origin in bats and overall symptoms are similar to those of its cousin coronaviruses. |
So scientists cannot say whether touching a surface with a smidgen of virus or breathing air with a few droplets exhaled by a sick person will make you ill. But it is safe to say exposure to more of the coronavirus is more likely to cause infection, and also to lead to more severe symptoms. That’s why it’s important to avoid crowded indoor spaces, wear masks and wash your hands. Each of those steps can decrease your chances of being exposed to large amounts of virus. | So scientists cannot say whether touching a surface with a smidgen of virus or breathing air with a few droplets exhaled by a sick person will make you ill. But it is safe to say exposure to more of the coronavirus is more likely to cause infection, and also to lead to more severe symptoms. That’s why it’s important to avoid crowded indoor spaces, wear masks and wash your hands. Each of those steps can decrease your chances of being exposed to large amounts of virus. |
By Roni Caryn Rabin | By Roni Caryn Rabin |
Covid-19 is a mercurial disease. While some people experience only mild, fleeting symptoms, others are knocked over with a severe flulike illness that can last several weeks. A minority of patients develop life-threatening complications. Death can ensue. | Covid-19 is a mercurial disease. While some people experience only mild, fleeting symptoms, others are knocked over with a severe flulike illness that can last several weeks. A minority of patients develop life-threatening complications. Death can ensue. |
Why do some people sail through the illness, and others develop the severe inflammation and lung damage that are hallmarks of the disease? It is one of the great mysteries of Covid-19. | Why do some people sail through the illness, and others develop the severe inflammation and lung damage that are hallmarks of the disease? It is one of the great mysteries of Covid-19. |
Experts say the patient’s immune response to the viral infection determines the severity of the illness. If the immune system goes into overdrive, it can trigger a cascade of harmful effects, injuring the lungs and other organs. | Experts say the patient’s immune response to the viral infection determines the severity of the illness. If the immune system goes into overdrive, it can trigger a cascade of harmful effects, injuring the lungs and other organs. |
Immune function declines with age, and elderly people with Covid-19 are among the most vulnerable to poor outcomes, as are those with chronic health conditions like high blood pressure, diabetes and cardiovascular disease. Obesity, which affects 4 in 10 American adults, also appears to exacerbate the illness. | Immune function declines with age, and elderly people with Covid-19 are among the most vulnerable to poor outcomes, as are those with chronic health conditions like high blood pressure, diabetes and cardiovascular disease. Obesity, which affects 4 in 10 American adults, also appears to exacerbate the illness. |
Men are at greater risk for critical illness and death, a sex disparity that may be explained by women’s more robust immune systems, scientists say. | Men are at greater risk for critical illness and death, a sex disparity that may be explained by women’s more robust immune systems, scientists say. |
Generally speaking, patients get sicker faster if they are exposed to a large dose of the virus when they are first infected, said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University. | Generally speaking, patients get sicker faster if they are exposed to a large dose of the virus when they are first infected, said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University. |
Much scientific inquiry has focused on the role of a receptor called angiotensin-converting enzyme 2, or ACE2, which is the entry way for coronaviruses into the cells. The receptor is found on the outer surfaces of cells in the lungs, blood vessels, intestines and other organs, as well as in the back of the throat and high up in the nasal passage. | Much scientific inquiry has focused on the role of a receptor called angiotensin-converting enzyme 2, or ACE2, which is the entry way for coronaviruses into the cells. The receptor is found on the outer surfaces of cells in the lungs, blood vessels, intestines and other organs, as well as in the back of the throat and high up in the nasal passage. |
When the pandemic started, there was concern that people taking blood pressure medications like ACE inhibitors could be at greater risk from the coronavirus, but so far studies have not found that to be the case, and doctors are urging patients to continue their medications. | When the pandemic started, there was concern that people taking blood pressure medications like ACE inhibitors could be at greater risk from the coronavirus, but so far studies have not found that to be the case, and doctors are urging patients to continue their medications. |
Though the SARS-CoV-2 virus attaches to the receptor in order to penetrate cells, ACE2 also helps regulate blood pressure and inflammation. Some scientists have suggested that children may be less susceptible to infection with Covid-19 because they have fewer of these receptors. ACE2 is also regulated differently in men and women, according to scientists who study sex differences in medicine, and men tend to develop hypertension, or high blood pressure, at younger ages than women. But much is still unknown. | Though the SARS-CoV-2 virus attaches to the receptor in order to penetrate cells, ACE2 also helps regulate blood pressure and inflammation. Some scientists have suggested that children may be less susceptible to infection with Covid-19 because they have fewer of these receptors. ACE2 is also regulated differently in men and women, according to scientists who study sex differences in medicine, and men tend to develop hypertension, or high blood pressure, at younger ages than women. But much is still unknown. |
“ACE2 can play two very critical roles, getting the virus into the cell, but also modulating some of the damage that takes place in the blood vessels and the lungs,” said Dr. Ankit B. Patel, a nephrologist at Brigham and Women’s Hospital in Boston. “So it’s a double-edged sword in a sense, and that’s made the whole story all the more complicated.” | “ACE2 can play two very critical roles, getting the virus into the cell, but also modulating some of the damage that takes place in the blood vessels and the lungs,” said Dr. Ankit B. Patel, a nephrologist at Brigham and Women’s Hospital in Boston. “So it’s a double-edged sword in a sense, and that’s made the whole story all the more complicated.” |
By Pam Belluck | By Pam Belluck |
There are many crucial unresolved questions about children and Covid-19. Finding the answers is not only important for them and their families, but for society at large, as communities plan to reopen schools, day care centers, playgrounds and other places children frequent. | There are many crucial unresolved questions about children and Covid-19. Finding the answers is not only important for them and their families, but for society at large, as communities plan to reopen schools, day care centers, playgrounds and other places children frequent. |
Updated June 30, 2020 | |
Common symptoms include fever, a dry cough, fatigue and difficulty breathing or shortness of breath. Some of these symptoms overlap with those of the flu, making detection difficult, but runny noses and stuffy sinuses are less common. The C.D.C. has also added chills, muscle pain, sore throat, headache and a new loss of the sense of taste or smell as symptoms to look out for. Most people fall ill five to seven days after exposure, but symptoms may appear in as few as two days or as many as 14 days. | |
Scientists around the country have tried to identify everyday materials that do a good job of filtering microscopic particles. In recent tests, HEPA furnace filters scored high, as did vacuum cleaner bags, fabric similar to flannel pajamas and those of 600-count pillowcases. Other materials tested included layered coffee filters and scarves and bandannas. These scored lower, but still captured a small percentage of particles. | Scientists around the country have tried to identify everyday materials that do a good job of filtering microscopic particles. In recent tests, HEPA furnace filters scored high, as did vacuum cleaner bags, fabric similar to flannel pajamas and those of 600-count pillowcases. Other materials tested included layered coffee filters and scarves and bandannas. These scored lower, but still captured a small percentage of particles. |
A commentary published this month on the website of the British Journal of Sports Medicine points out that covering your face during exercise “comes with issues of potential breathing restriction and discomfort” and requires “balancing benefits versus possible adverse events.” Masks do alter exercise, says Cedric X. Bryant, the president and chief science officer of the American Council on Exercise, a nonprofit organization that funds exercise research and certifies fitness professionals. “In my personal experience,” he says, “heart rates are higher at the same relative intensity when you wear a mask.” Some people also could experience lightheadedness during familiar workouts while masked, says Len Kravitz, a professor of exercise science at the University of New Mexico. | 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. |
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. |
One puzzle is what role children play in spreading the virus. They seem less likely to become seriously ill than adults, making up about 2 percent of confirmed American coronavirus cases. There are different theories about whether that is because children are less likely to become infected to begin with, or whether the virus infects them just as easily but mostly causes few or no symptoms. | One puzzle is what role children play in spreading the virus. They seem less likely to become seriously ill than adults, making up about 2 percent of confirmed American coronavirus cases. There are different theories about whether that is because children are less likely to become infected to begin with, or whether the virus infects them just as easily but mostly causes few or no symptoms. |
Either way, a growing body of evidence suggests that infected children can transmit the virus, possibly as easily as adults. And one recent study suggests that when children attend school, they come in contact with three times as many people as average adults do, providing more opportunities for children to become infected and infect others. | Either way, a growing body of evidence suggests that infected children can transmit the virus, possibly as easily as adults. And one recent study suggests that when children attend school, they come in contact with three times as many people as average adults do, providing more opportunities for children to become infected and infect others. |
Although far fewer children than adults have experienced severe symptoms, some children have become devastatingly ill and there have been at least 20 deaths of children from Covid-19 in the United States and elsewhere. Reports from hospitals suggest that the children most vulnerable to the respiratory failure adults develop are those who already have a serious medical condition. Some studies also suggest that infants and preschoolers may be more vulnerable than older children. | Although far fewer children than adults have experienced severe symptoms, some children have become devastatingly ill and there have been at least 20 deaths of children from Covid-19 in the United States and elsewhere. Reports from hospitals suggest that the children most vulnerable to the respiratory failure adults develop are those who already have a serious medical condition. Some studies also suggest that infants and preschoolers may be more vulnerable than older children. |
But a small number of other children, including teenagers, who did not have any symptoms when they were first infected, have developed a newly-identified inflammatory syndrome that can cause serious heart problems. The syndrome, which seems to occur weeks after infection and to result from a revved-up immune response to the virus, has been reported in Europe and throughout the United States and has caused several deaths. Doctors are urgently trying to understand what causes the syndrome, why it afflicts some children and not others, and how to best treat or prevent it. | But a small number of other children, including teenagers, who did not have any symptoms when they were first infected, have developed a newly-identified inflammatory syndrome that can cause serious heart problems. The syndrome, which seems to occur weeks after infection and to result from a revved-up immune response to the virus, has been reported in Europe and throughout the United States and has caused several deaths. Doctors are urgently trying to understand what causes the syndrome, why it afflicts some children and not others, and how to best treat or prevent it. |
By Benedict Carey | By Benedict Carey |
The notion of a single patient zero is both theatrical and real: In any new epidemic, some unlucky soul seeds the first infection, several links of which are fated to seed chains of their own and spark a viral Big Bang. | The notion of a single patient zero is both theatrical and real: In any new epidemic, some unlucky soul seeds the first infection, several links of which are fated to seed chains of their own and spark a viral Big Bang. |
By analyzing the genetic material of people who test positive, scientists can trace the lineage of each virus back to a common ancestor, and often to an individual carrier. The first confirmed coronavirus case in the United States was a man who landed at Seattle-Tacoma Airport on Jan. 15, from China. Other introductions came in February, and scientists are now closing in on who, exactly, sparked the outbreak in Washington State. | By analyzing the genetic material of people who test positive, scientists can trace the lineage of each virus back to a common ancestor, and often to an individual carrier. The first confirmed coronavirus case in the United States was a man who landed at Seattle-Tacoma Airport on Jan. 15, from China. Other introductions came in February, and scientists are now closing in on who, exactly, sparked the outbreak in Washington State. |
New York confirmed its first case on March 1, and by that time there were already thousands of infected people walking around, for a week or more. Scientists have found genetic signatures on the viruses studied so far that link them to Europe, likely brought in by some of the millions of people arriving in New York in February, and it is likely that there were multiple introductions that spread widely: patients zero, plural. | New York confirmed its first case on March 1, and by that time there were already thousands of infected people walking around, for a week or more. Scientists have found genetic signatures on the viruses studied so far that link them to Europe, likely brought in by some of the millions of people arriving in New York in February, and it is likely that there were multiple introductions that spread widely: patients zero, plural. |
The first infected arrivals in a community are not necessarily the ones who light the fuse. In a report published last week, genetic scientists argued that infected people were among both Americans and Europeans in January, but that most of those viruses fizzled out. And French doctors recently reported that a respiratory sample from a man hospitalized near Paris, in late December, tested positive. That virus, too, likely died out. France’s outbreak did not start until many weeks later. | The first infected arrivals in a community are not necessarily the ones who light the fuse. In a report published last week, genetic scientists argued that infected people were among both Americans and Europeans in January, but that most of those viruses fizzled out. And French doctors recently reported that a respiratory sample from a man hospitalized near Paris, in late December, tested positive. That virus, too, likely died out. France’s outbreak did not start until many weeks later. |
The world’s patient zero, in China, began infecting others in the late fall of last year, the evidence thus far suggests. An analysis of the first 41 confirmed cases, all in people who had visited the same seafood market in Wuhan, indicates that the first hospital admission was on Dec. 16, 2019. The patient first noticed symptoms on Dec. 1, so the infection dates back earlier. Several scientists have estimated that the first outbreak began in late or mid-November, and have inferred a probable common viral ancestor, though additional virus samples could change the picture. | The world’s patient zero, in China, began infecting others in the late fall of last year, the evidence thus far suggests. An analysis of the first 41 confirmed cases, all in people who had visited the same seafood market in Wuhan, indicates that the first hospital admission was on Dec. 16, 2019. The patient first noticed symptoms on Dec. 1, so the infection dates back earlier. Several scientists have estimated that the first outbreak began in late or mid-November, and have inferred a probable common viral ancestor, though additional virus samples could change the picture. |
The level of detective work required to find the actual patient zero might be steeper than it appears. At least one genetic scientist has argued that the virus could have first infected humans — likely from a pangolin — well before last fall, in a form that did not cause sickness. It then evolved its pathogenic features over time, while circulating. If that’s the case, the question “Who came first?” may go without a conclusive answer for some time, perhaps for good. | The level of detective work required to find the actual patient zero might be steeper than it appears. At least one genetic scientist has argued that the virus could have first infected humans — likely from a pangolin — well before last fall, in a form that did not cause sickness. It then evolved its pathogenic features over time, while circulating. If that’s the case, the question “Who came first?” may go without a conclusive answer for some time, perhaps for good. |
By Apoorva Mandavilli | By Apoorva Mandavilli |
Are people infected with the coronavirus protected from further infection? And, if yes, for how long? | Are people infected with the coronavirus protected from further infection? And, if yes, for how long? |
The answers to these questions have broad implications for reopening the economy and allowing the public to live with less fear of infection in the short term — and for the effectiveness of vaccines in the long term. | The answers to these questions have broad implications for reopening the economy and allowing the public to live with less fear of infection in the short term — and for the effectiveness of vaccines in the long term. |
Scientists have made steady, if incremental, progress in getting to the answers. When the body encounters any virus, it typically makes antibodies, some of which are powerful enough to neutralize the pathogen and prevent reinfection. It also produces large numbers of immune cells that can kill the virus. | Scientists have made steady, if incremental, progress in getting to the answers. When the body encounters any virus, it typically makes antibodies, some of which are powerful enough to neutralize the pathogen and prevent reinfection. It also produces large numbers of immune cells that can kill the virus. |
Most tests that look for antibodies to the coronavirus have been flawed. But at least one team with a reliable test reported that most people, including those who were only mildly ill, make powerful antibodies. Data on immune cells has been slower to emerge, but a few studies suggest a robust response from immune cells as well. | Most tests that look for antibodies to the coronavirus have been flawed. But at least one team with a reliable test reported that most people, including those who were only mildly ill, make powerful antibodies. Data on immune cells has been slower to emerge, but a few studies suggest a robust response from immune cells as well. |
What remains unknown is how long this immunity will last. There have been some reports of reinfection, but scientists have said that they are a result either of faulty testing, or of viral remnants that circulate long after the active infection has ended. | What remains unknown is how long this immunity will last. There have been some reports of reinfection, but scientists have said that they are a result either of faulty testing, or of viral remnants that circulate long after the active infection has ended. |
They are hopeful that based on other coronaviruses that cause the common cold, SARS or MERS, immunity to the new coronavirus might last at least a year, but it remains a mystery for now. | They are hopeful that based on other coronaviruses that cause the common cold, SARS or MERS, immunity to the new coronavirus might last at least a year, but it remains a mystery for now. |