This article is from the source 'nytimes' and was first published or seen on . It last changed over 40 days ago and won't be checked again for changes.

You can find the current article at its original source at https://www.nytimes.com/2020/05/27/health/coronavirus-spread-united-states.html

The article has changed 28 times. There is an RSS feed of changes available.

Version 3 Version 4
Coronavirus Epidemics Began Later Than Believed, Study Concludes Coronavirus Epidemics Began Later Than Believed, Study Concludes
(3 days later)
The first confirmed coronavirus infections in Europe and the United States, discovered in January, did not ignite the epidemics that followed, according to a close analysis of hundreds of viral genomes.The first confirmed coronavirus infections in Europe and the United States, discovered in January, did not ignite the epidemics that followed, according to a close analysis of hundreds of viral genomes.
Instead, the outbreaks plaguing much of the West began weeks later, the study concluded. The revised timeline may clarify nagging ambiguities about the arrival of the pandemic.Instead, the outbreaks plaguing much of the West began weeks later, the study concluded. The revised timeline may clarify nagging ambiguities about the arrival of the pandemic.
For example, while President Trump has frequently claimed that a ban on travelers from China prevented the epidemic from becoming much worse, the new data suggest that the virus that started Washington State’s epidemic arrived roughly two weeks after the ban was imposed on Feb. 2.For example, while President Trump has frequently claimed that a ban on travelers from China prevented the epidemic from becoming much worse, the new data suggest that the virus that started Washington State’s epidemic arrived roughly two weeks after the ban was imposed on Feb. 2.
And the authors argue that the relatively late emergence of the outbreak means that more lives could have been saved by early action, such as testing and contact tracing.And the authors argue that the relatively late emergence of the outbreak means that more lives could have been saved by early action, such as testing and contact tracing.
The new analysis is not the last word. Scientific understanding of the coronavirus is evolving almost daily, and this type of research yields a range of possible results, not complete certainty.The new analysis is not the last word. Scientific understanding of the coronavirus is evolving almost daily, and this type of research yields a range of possible results, not complete certainty.
Many infections in Washington State seem to have occurred in early February, and other models suggested that the epidemic there began closer to the beginning of the month.Many infections in Washington State seem to have occurred in early February, and other models suggested that the epidemic there began closer to the beginning of the month.
But a number of virus experts said that the new report convincingly rules out a connection between the first confirmed cases and the later outbreaks.But a number of virus experts said that the new report convincingly rules out a connection between the first confirmed cases and the later outbreaks.
“This paper clearly shows this didn’t happen,” said Kristian Andersen, a computational biologist at the Scripps Research Institute in San Diego, who was not involved in the research.“This paper clearly shows this didn’t happen,” said Kristian Andersen, a computational biologist at the Scripps Research Institute in San Diego, who was not involved in the research.
Michael Worobey, an evolutionary biologist at the University of Arizona, and his colleagues posted a preliminary version of their study online on Saturday. It has not yet been published in a scientific journal.Michael Worobey, an evolutionary biologist at the University of Arizona, and his colleagues posted a preliminary version of their study online on Saturday. It has not yet been published in a scientific journal.
Viruses develop genetic mutations at a roughly regular rate as they multiply. Scientists can use these mutations to reconstruct a virus’s movement through a population and to estimate when an outbreak began in a region.Viruses develop genetic mutations at a roughly regular rate as they multiply. Scientists can use these mutations to reconstruct a virus’s movement through a population and to estimate when an outbreak began in a region.
The first confirmed coronavirus case in the United States was a man who flew from China to the Seattle-Tacoma International Airport on Jan. 15. Researchers sequenced the genome of his virus, which came to be known as WA1.The first confirmed coronavirus case in the United States was a man who flew from China to the Seattle-Tacoma International Airport on Jan. 15. Researchers sequenced the genome of his virus, which came to be known as WA1.
The man, who lived in Snohomish County, was hospitalized in isolation and recovered. On Feb. 24, a Snohomish teenager with flulike symptoms also tested positive for the coronavirus.The man, who lived in Snohomish County, was hospitalized in isolation and recovered. On Feb. 24, a Snohomish teenager with flulike symptoms also tested positive for the coronavirus.
Trevor Bedford, a geneticist at the University of Washington and the Fred Hutchinson Cancer Research Center, and his colleagues discovered that this viral genome was nearly identical to WA1, except for two new mutations. They called the second virus WA2.Trevor Bedford, a geneticist at the University of Washington and the Fred Hutchinson Cancer Research Center, and his colleagues discovered that this viral genome was nearly identical to WA1, except for two new mutations. They called the second virus WA2.
Alarmed, he and his colleagues concluded that the most likely explanation for the slight difference was that WA1 had circulated in Washington State for six weeks, gaining the mutations along the way.Alarmed, he and his colleagues concluded that the most likely explanation for the slight difference was that WA1 had circulated in Washington State for six weeks, gaining the mutations along the way.
The implication was that there might be hundreds of people already infected in the state, setting the stage for an explosion of cases. Officials reacted to the news with aggressive measures that public health experts credit with reining in the outbreak.The implication was that there might be hundreds of people already infected in the state, setting the stage for an explosion of cases. Officials reacted to the news with aggressive measures that public health experts credit with reining in the outbreak.
Initially, Dr. Worobey found the work by Dr. Bedford and his colleagues “pretty darn convincing.” But as time passed, he said in an interview, “something at the back of my mind started niggling away.”Initially, Dr. Worobey found the work by Dr. Bedford and his colleagues “pretty darn convincing.” But as time passed, he said in an interview, “something at the back of my mind started niggling away.”
Viruses are far more prone to genetic mutations than other living things. But as viruses go, the new coronavirus is a slowpoke — much more stable than influenza viruses, for example.Viruses are far more prone to genetic mutations than other living things. But as viruses go, the new coronavirus is a slowpoke — much more stable than influenza viruses, for example.
It seemed unlikely to Dr. Worobey for the coronavirus to have gained two mutations in just weeks.It seemed unlikely to Dr. Worobey for the coronavirus to have gained two mutations in just weeks.
As the epidemic spread, Dr. Bedford and his colleagues examined hundreds of coronavirus genomes from Washington State. None of the genomes matched WA1. They all shared the two mutations found in WA2.As the epidemic spread, Dr. Bedford and his colleagues examined hundreds of coronavirus genomes from Washington State. None of the genomes matched WA1. They all shared the two mutations found in WA2.
Dr. Worobey and his colleagues decided to take a further look. They replayed the outbreak thousands of times on a computer running a program that simulates what we know so far about how the new coronavirus spreads and mutates.Dr. Worobey and his colleagues decided to take a further look. They replayed the outbreak thousands of times on a computer running a program that simulates what we know so far about how the new coronavirus spreads and mutates.
When the researchers modeled WA1 as the source of the Washington State outbreak, the computer could not reproduce the viral mutations found there in later weeks. It was close to impossible for WA1 to have seeded the outbreak, the scientists decided.When the researchers modeled WA1 as the source of the Washington State outbreak, the computer could not reproduce the viral mutations found there in later weeks. It was close to impossible for WA1 to have seeded the outbreak, the scientists decided.
It was far more likely that the WA2 group of viruses was introduced to Washington from China sometime around Feb. 13th and set off the epidemic.It was far more likely that the WA2 group of viruses was introduced to Washington from China sometime around Feb. 13th and set off the epidemic.
That was about two weeks after Mr. Trump banned most travelers from China. According to an analysis by The New York Times, however, about 40,000 people made the journey to the United States in the two months after those restrictions were imposed.That was about two weeks after Mr. Trump banned most travelers from China. According to an analysis by The New York Times, however, about 40,000 people made the journey to the United States in the two months after those restrictions were imposed.
Many were admitted under rules that exempted American citizens and others. They were funneled to a few international hubs, including Seattle-Tacoma International Airport.Many were admitted under rules that exempted American citizens and others. They were funneled to a few international hubs, including Seattle-Tacoma International Airport.
Dr. Worobey speculated that the virus that started the state’s epidemic arrived by that route, or perhaps to the Seattle area via Vancouver. There was no stealthy community spread of the coronavirus in January in the state, the analysis concluded; the epidemic began soon after the virus that started it arrived.Dr. Worobey speculated that the virus that started the state’s epidemic arrived by that route, or perhaps to the Seattle area via Vancouver. There was no stealthy community spread of the coronavirus in January in the state, the analysis concluded; the epidemic began soon after the virus that started it arrived.
In an interview, Dr. Bedford said of the new research, “I think it’s a very clever way to do things.” On Twitter, he accepted many of the conclusions: “I believe I was wrong in the original assessment of a WA1 introduction,” he wrote.In an interview, Dr. Bedford said of the new research, “I think it’s a very clever way to do things.” On Twitter, he accepted many of the conclusions: “I believe I was wrong in the original assessment of a WA1 introduction,” he wrote.
Still, Dr. Bedford and his colleagues have continued their own study of the Washington State outbreak, and they now estimate it began around Feb. 1 — about two weeks earlier than Dr. Worobey’s estimate.Still, Dr. Bedford and his colleagues have continued their own study of the Washington State outbreak, and they now estimate it began around Feb. 1 — about two weeks earlier than Dr. Worobey’s estimate.
Dr. Bedford found it unlikely that a virus that appeared around Feb. 13 could produce a large outbreak by the end of the month. But Dr. Worobey’s team found a similar pattern in the arrival of the new coronavirus in Europe.Dr. Bedford found it unlikely that a virus that appeared around Feb. 13 could produce a large outbreak by the end of the month. But Dr. Worobey’s team found a similar pattern in the arrival of the new coronavirus in Europe.
On Jan. 20, a woman who had traveled from China to Germany met with her colleagues at an auto supply company. She didn’t realize she was sick, and infected a man at the meeting.On Jan. 20, a woman who had traveled from China to Germany met with her colleagues at an auto supply company. She didn’t realize she was sick, and infected a man at the meeting.
Updated June 2, 2020 Updated June 5, 2020
The unemployment rate fell to 13.3 percent in May, the Labor Department said on June 5, an unexpected improvement in the nation’s job market as hiring rebounded faster than economists expected. Economists had forecast the unemployment rate to increase to as much as 20 percent, after it hit 14.7 percent in April, which was the highest since the government began keeping official statistics after World War II. But the unemployment rate dipped instead, with employers adding 2.5 million jobs, after more than 20 million jobs were lost in April.
Mass protests against police brutality that have brought thousands of people onto the streets in cities across America are raising the specter of new coronavirus outbreaks, prompting political leaders, physicians and public health experts to warn that the crowds could cause a surge in cases. While many political leaders affirmed the right of protesters to express themselves, they urged the demonstrators to wear face masks and maintain social distancing, both to protect themselves and to prevent further community spread of the virus. Some infectious disease experts were reassured by the fact that the protests were held outdoors, saying the open air settings could mitigate the risk of transmission.Mass protests against police brutality that have brought thousands of people onto the streets in cities across America are raising the specter of new coronavirus outbreaks, prompting political leaders, physicians and public health experts to warn that the crowds could cause a surge in cases. While many political leaders affirmed the right of protesters to express themselves, they urged the demonstrators to wear face masks and maintain social distancing, both to protect themselves and to prevent further community spread of the virus. Some infectious disease experts were reassured by the fact that the protests were held outdoors, saying the open air settings could mitigate the risk of transmission.
Exercise researchers and physicians have some blunt advice for those of us aiming to return to regular exercise now: Start slowly and then rev up your workouts, also slowly. American adults tended to be about 12 percent less active after the stay-at-home mandates began in March than they were in January. But there are steps you can take to ease your way back into regular exercise safely. First, “start at no more than 50 percent of the exercise you were doing before Covid,” says Dr. Monica Rho, the chief of musculoskeletal medicine at the Shirley Ryan AbilityLab in Chicago. Thread in some preparatory squats, too, she advises. “When you haven’t been exercising, you lose muscle mass.” Expect some muscle twinges after these preliminary, post-lockdown sessions, especially a day or two later. But sudden or increasing pain during exercise is a clarion call to stop and return home.Exercise researchers and physicians have some blunt advice for those of us aiming to return to regular exercise now: Start slowly and then rev up your workouts, also slowly. American adults tended to be about 12 percent less active after the stay-at-home mandates began in March than they were in January. But there are steps you can take to ease your way back into regular exercise safely. First, “start at no more than 50 percent of the exercise you were doing before Covid,” says Dr. Monica Rho, the chief of musculoskeletal medicine at the Shirley Ryan AbilityLab in Chicago. Thread in some preparatory squats, too, she advises. “When you haven’t been exercising, you lose muscle mass.” Expect some muscle twinges after these preliminary, post-lockdown sessions, especially a day or two later. But sudden or increasing pain during exercise is a clarion call to stop and return home.
States are reopening bit by bit. This means that more public spaces are available for use and more and more businesses are being allowed to open again. The federal government is largely leaving the decision up to states, and some state leaders are leaving the decision up to local authorities. Even if you aren’t being told to stay at home, it’s still a good idea to limit trips outside and your interaction with other people.States are reopening bit by bit. This means that more public spaces are available for use and more and more businesses are being allowed to open again. The federal government is largely leaving the decision up to states, and some state leaders are leaving the decision up to local authorities. Even if you aren’t being told to stay at home, it’s still a good idea to limit trips outside and your interaction with other people.
Touching contaminated objects and then infecting ourselves with the germs is not typically how the virus spreads. But it can happen. A number of studies of flu, rhinovirus, coronavirus and other microbes have shown that respiratory illnesses, including the new coronavirus, can spread by touching contaminated surfaces, particularly in places like day care centers, offices and hospitals. But a long chain of events has to happen for the disease to spread that way. The best way to protect yourself from coronavirus — whether it’s surface transmission or close human contact — is still social distancing, washing your hands, not touching your face and wearing masks.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.
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.
Scientists gathered that virus’s genetic signature and called it BavPat1. That virus spread to 16 people in the company — but then disappeared.Scientists gathered that virus’s genetic signature and called it BavPat1. That virus spread to 16 people in the company — but then disappeared.
At the end of February, Italy saw Europe’s first outbreak. The coronaviruses there were genetically very close to BavPat1, scientists found, leading to suspicions that a German traveler had brought the virus to Italy.At the end of February, Italy saw Europe’s first outbreak. The coronaviruses there were genetically very close to BavPat1, scientists found, leading to suspicions that a German traveler had brought the virus to Italy.
That’s not the case, according to Dr. Worobey’s analysis. According to the computer simulations, another introduction of the coronavirus from China probably was responsible, and it may have arrived in early or mid-February.That’s not the case, according to Dr. Worobey’s analysis. According to the computer simulations, another introduction of the coronavirus from China probably was responsible, and it may have arrived in early or mid-February.
“The lineage just happened to get into Europe and run wild,” Dr. Worobey said.“The lineage just happened to get into Europe and run wild,” Dr. Worobey said.
This viral line then hopped from Europe to New York several times, Dr. Worobey and his colleagues found, confirming previous studies. They estimated that the coronaviruses circulating in the city by March were introduced into the city around Feb. 20.This viral line then hopped from Europe to New York several times, Dr. Worobey and his colleagues found, confirming previous studies. They estimated that the coronaviruses circulating in the city by March were introduced into the city around Feb. 20.
Around the world, the new study suggests, the coronavirus arrived more than once without starting runaway outbreaks. In these cases, there was little or no transmission, and the virus simply died out.Around the world, the new study suggests, the coronavirus arrived more than once without starting runaway outbreaks. In these cases, there was little or no transmission, and the virus simply died out.
To Dr. Worobey, the time before the pandemic took off in the United States was a lost opportunity, when testing and contact tracing could have made a big difference.To Dr. Worobey, the time before the pandemic took off in the United States was a lost opportunity, when testing and contact tracing could have made a big difference.
“There were weeks before the virus really got a foothold,” he said. “It does start to make those missteps seem much more consequential.”“There were weeks before the virus really got a foothold,” he said. “It does start to make those missteps seem much more consequential.”
The study is “a very careful and rigorous analysis of what we can and can’t say about the U.S. and European outbreaks from genomic data,” said Edward Holmes, a virologist at the University of Sydney who was not involved in the study.The study is “a very careful and rigorous analysis of what we can and can’t say about the U.S. and European outbreaks from genomic data,” said Edward Holmes, a virologist at the University of Sydney who was not involved in the study.
“To me, what this all highlights are the challenges about drawing strong conclusions on virus introductions and spread based on limited data.”“To me, what this all highlights are the challenges about drawing strong conclusions on virus introductions and spread based on limited data.”
This updated view of the history of the pandemic is exactly how science is supposed to work, said Dr. Andersen of Scripps Research. Scientists look for the best interpretation of data — and then keep looking.This updated view of the history of the pandemic is exactly how science is supposed to work, said Dr. Andersen of Scripps Research. Scientists look for the best interpretation of data — and then keep looking.
But it can be unsettling for the public to watch scientific consensus shift in real time.But it can be unsettling for the public to watch scientific consensus shift in real time.
“We have to live with that uncertainty,” Dr. Andersen said.“We have to live with that uncertainty,” Dr. Andersen said.