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The Pandemic’s Big Mystery: How Deadly Is the Coronavirus? The Pandemic’s Big Mystery: How Deadly Is the Coronavirus?
(about 1 hour later)
More than six months into the pandemic, the coronavirus has infected more than 11 million people worldwide, killing more than 525,000. But despite the increasing toll, scientists still do not have a definitive answer to one of the most fundamental questions about the virus: How deadly is it?More than six months into the pandemic, the coronavirus has infected more than 11 million people worldwide, killing more than 525,000. But despite the increasing toll, scientists still do not have a definitive answer to one of the most fundamental questions about the virus: How deadly is it?
A firm estimate could help governments predict how many deaths would ensue if the virus spread out of control. The figure, usually called the infection fatality rate, could tell health officials what to expect as the pandemic spreads to densely populated nations like Brazil, Nigeria and India.A firm estimate could help governments predict how many deaths would ensue if the virus spread out of control. The figure, usually called the infection fatality rate, could tell health officials what to expect as the pandemic spreads to densely populated nations like Brazil, Nigeria and India.
In even poorer countries, where lethal threats like measles and malaria are constant and where hard budget choices are routine, the number could help officials decide whether to spend more on oxygen concentrators or ventilators, or on measles shots and mosquito nets.In even poorer countries, where lethal threats like measles and malaria are constant and where hard budget choices are routine, the number could help officials decide whether to spend more on oxygen concentrators or ventilators, or on measles shots and mosquito nets.
The question became even more complex last month, when the Centers for Disease Control and Prevention released data suggesting that for every documented infection in the United States, there were 10 other cases on average that had gone unrecorded, probably because they were very mild or asymptomatic.The question became even more complex last month, when the Centers for Disease Control and Prevention released data suggesting that for every documented infection in the United States, there were 10 other cases on average that had gone unrecorded, probably because they were very mild or asymptomatic.
If there are many more asymptomatic infections than once thought, then the virus may be less deadly than it has appeared. But even that calculation is a difficult one.If there are many more asymptomatic infections than once thought, then the virus may be less deadly than it has appeared. But even that calculation is a difficult one.
On Thursday, after the World Health Organization held a two-day online meeting of 1,300 scientists from around the world, the agency’s chief scientist, Dr. Soumya Swaminathan, said the consensus for now was that the I.F.R. is about 0.6 percent — which means that the risk of death is less than 1 percent.On Thursday, after the World Health Organization held a two-day online meeting of 1,300 scientists from around the world, the agency’s chief scientist, Dr. Soumya Swaminathan, said the consensus for now was that the I.F.R. is about 0.6 percent — which means that the risk of death is less than 1 percent.
Although she did not note this, 0.6 percent of the world’s population is 47 million people, and 0.6 percent of the American population is 2 million people. The virus remains a major threat.Although she did not note this, 0.6 percent of the world’s population is 47 million people, and 0.6 percent of the American population is 2 million people. The virus remains a major threat.
At present, countries have very different case fatality rates, or C.F.R.’s, which measure deaths among patients known to have had Covid-19. In most cases, that number is highest in countries that have had the virus the longest.At present, countries have very different case fatality rates, or C.F.R.’s, which measure deaths among patients known to have had Covid-19. In most cases, that number is highest in countries that have had the virus the longest.
According to data gathered by The New York Times, China had reported 90,294 cases as of Friday and 4,634 deaths, which is a C.F.R. of 5 percent. The United States was very close to that mark. It has had 2,811,447 cases and 129,403 deaths, about 4.6 percent.According to data gathered by The New York Times, China had reported 90,294 cases as of Friday and 4,634 deaths, which is a C.F.R. of 5 percent. The United States was very close to that mark. It has had 2,811,447 cases and 129,403 deaths, about 4.6 percent.
Those percentages are far higher rates than the 2.5 percent death rate often ascribed to the 1918 flu pandemic. Still, it is difficult to measure fatality rates during pandemics, especially at the beginning.Those percentages are far higher rates than the 2.5 percent death rate often ascribed to the 1918 flu pandemic. Still, it is difficult to measure fatality rates during pandemics, especially at the beginning.
In the chaos that ensues when a new virus hits a city hard, thousands of people may die and be buried without ever being tested, and certainly without them all being autopsied.In the chaos that ensues when a new virus hits a city hard, thousands of people may die and be buried without ever being tested, and certainly without them all being autopsied.
It is never entirely clear how many died of the virus and how many died of heart attacks, strokes or other ills. That has happened in both New York City and in Wuhan, China, where the outbreak began.It is never entirely clear how many died of the virus and how many died of heart attacks, strokes or other ills. That has happened in both New York City and in Wuhan, China, where the outbreak began.
Normally, once the chaos has subsided, more testing is done and more mild cases are found — and because the denominator of the fraction rises, fatality rates fall. But the results are not always consistent or predictable.Normally, once the chaos has subsided, more testing is done and more mild cases are found — and because the denominator of the fraction rises, fatality rates fall. But the results are not always consistent or predictable.
Ten sizable countries, most of them in Western Europe, have tested bigger percentages of their populations than has the United States, according to Worldometer, which gathers statistics. They are Iceland, Denmark, Spain, Portugal, Belgium, Ireland, Italy, Britain, Israel and New Zealand.Ten sizable countries, most of them in Western Europe, have tested bigger percentages of their populations than has the United States, according to Worldometer, which gathers statistics. They are Iceland, Denmark, Spain, Portugal, Belgium, Ireland, Italy, Britain, Israel and New Zealand.
But their case fatality rates vary wildly: Iceland’s is less than 1 percent, New Zealand’s and Israel’s are below 2 percent. Belgium, by comparison, is at 16 percent, and Italy and Britain at 14 percent.But their case fatality rates vary wildly: Iceland’s is less than 1 percent, New Zealand’s and Israel’s are below 2 percent. Belgium, by comparison, is at 16 percent, and Italy and Britain at 14 percent.
Both figures — the infection fatality rate and the case fatality rate — can differ quite a bit by country.Both figures — the infection fatality rate and the case fatality rate — can differ quite a bit by country.
So far, in most countries, about 20 percent of all confirmed Covid-19 patients become ill enough to need supplemental oxygen or even more advanced hospital care, said Dr. Janet Diaz, head of clinical care for the W.H.O.’s emergencies program.So far, in most countries, about 20 percent of all confirmed Covid-19 patients become ill enough to need supplemental oxygen or even more advanced hospital care, said Dr. Janet Diaz, head of clinical care for the W.H.O.’s emergencies program.
Whether those patients survive depends on a host of factors, including age, underlying illnesses and the level of medical care available.Whether those patients survive depends on a host of factors, including age, underlying illnesses and the level of medical care available.
Death rates are expected to be lower in countries with younger populations and less obesity, which are often the poorest countries. Conversely, the figures should be higher in countries that lack oxygen tanks, ventilators and dialysis machines, and where many people live far from hospitals. Those are also often the poorest countries.Death rates are expected to be lower in countries with younger populations and less obesity, which are often the poorest countries. Conversely, the figures should be higher in countries that lack oxygen tanks, ventilators and dialysis machines, and where many people live far from hospitals. Those are also often the poorest countries.
The W.H.O. and various charities are scrambling to purchase oxygen equipment for poor and middle-income nations in which the coronavirus is spreading.The W.H.O. and various charities are scrambling to purchase oxygen equipment for poor and middle-income nations in which the coronavirus is spreading.
And now, new factors are being introduced into the equation. For example, new evidence that people with Type A blood are more likely to fall deathly ill could change risk calculations. Type A blood is relatively rare in West Africa and South Asia, and very rare among the Indigenous peoples of South America.And now, new factors are being introduced into the equation. For example, new evidence that people with Type A blood are more likely to fall deathly ill could change risk calculations. Type A blood is relatively rare in West Africa and South Asia, and very rare among the Indigenous peoples of South America.
Before this week’s meeting, the W.H.O. had no official I.F.R. estimate, Oliver Morgan, the agency’s director of health emergency information and risk assessment, said in an interview in early June.Before this week’s meeting, the W.H.O. had no official I.F.R. estimate, Oliver Morgan, the agency’s director of health emergency information and risk assessment, said in an interview in early June.
Instead, it had relied on a mix of data sent in by member countries and by academic groups, and on a meta-analysis done in May by scientists at the University of Wollongong and James Cook University in Australia.Instead, it had relied on a mix of data sent in by member countries and by academic groups, and on a meta-analysis done in May by scientists at the University of Wollongong and James Cook University in Australia.
Those researchers looked at 267 studies in more than a dozen countries, and then chose the 25 they considered the most accurate, weighting them for accuracy and averaged the data. They concluded that the global I.F.R. was 0.64 percent.Those researchers looked at 267 studies in more than a dozen countries, and then chose the 25 they considered the most accurate, weighting them for accuracy and averaged the data. They concluded that the global I.F.R. was 0.64 percent.
Updated July 15, 2020Updated July 15, 2020
The coronavirus can stay aloft for hours in tiny droplets in stagnant air, infecting people as they inhale, mounting scientific evidence suggests. This risk is highest in crowded indoor spaces with poor ventilation, and may help explain super-spreading events reported in meatpacking plants, churches and restaurants. It’s unclear how often the virus is spread via these tiny droplets, or aerosols, compared with larger droplets that are expelled when a sick person coughs or sneezes, or transmitted through contact with contaminated surfaces, said Linsey Marr, an aerosol expert at Virginia Tech. Aerosols are released even when a person without symptoms exhales, talks or sings, according to Dr. Marr and more than 200 other experts, who have outlined the evidence in an open letter to the World Health Organization.
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.
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 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.
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.
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.
The C.D.C. relies on a “symptomatic case fatality ratio” that “is not necessarily equivalent to the number of reported deaths per reported cases.” The best estimate for the United States is 0.4 percent, according to a set of planning scenarios released in late May.The C.D.C. relies on a “symptomatic case fatality ratio” that “is not necessarily equivalent to the number of reported deaths per reported cases.” The best estimate for the United States is 0.4 percent, according to a set of planning scenarios released in late May.
The agency did not respond to requests to explain how it arrived at that figure, or why it was so much lower than the W.H.O.’s estimate. By comparison, 0.4 percent of the United States population is 1.3 million people.The agency did not respond to requests to explain how it arrived at that figure, or why it was so much lower than the W.H.O.’s estimate. By comparison, 0.4 percent of the United States population is 1.3 million people.
The 25 studies that the Australian researchers considered the most accurate relied on very different methodologies. One report, for example, was based on diagnostic PCR tests of all passengers and crew aboard the Diamond Princess, the cruise ship that docked in Japan after it was overcome by the coronavirus. Another study drew data from an antibody survey of 38,000 Spaniards, while another included only 1,104 Swedes.The 25 studies that the Australian researchers considered the most accurate relied on very different methodologies. One report, for example, was based on diagnostic PCR tests of all passengers and crew aboard the Diamond Princess, the cruise ship that docked in Japan after it was overcome by the coronavirus. Another study drew data from an antibody survey of 38,000 Spaniards, while another included only 1,104 Swedes.
The current W.H.O. estimate is based on later, larger studies of how many people have antibodies in their blood; future studies may further refine the figure, Dr. Swaminathan said.The current W.H.O. estimate is based on later, larger studies of how many people have antibodies in their blood; future studies may further refine the figure, Dr. Swaminathan said.
But there is “a lot of uncertainty” about how many silent and untested carriers there are, Dr. Morgan of the W.H.O. said.But there is “a lot of uncertainty” about how many silent and untested carriers there are, Dr. Morgan of the W.H.O. said.
To arrive at the C.D.C.’s new estimate, researchers tested samples from 11,933 people for antibodies to the coronavirus in six regions in the United States. New York City reported 53,803 cases by April 1, but the actual number of infections was 12 times higher — nearly 642,000, the agency estimated.To arrive at the C.D.C.’s new estimate, researchers tested samples from 11,933 people for antibodies to the coronavirus in six regions in the United States. New York City reported 53,803 cases by April 1, but the actual number of infections was 12 times higher — nearly 642,000, the agency estimated.
New York City’s prevalence of 7 percent in the C.D.C. study was well below the 21 percent estimated in a state survey in April. But that number was based on people recruited at supermarkets, and so the results may have been biased toward people out shopping during a pandemic — often the young, who have been less affected.New York City’s prevalence of 7 percent in the C.D.C. study was well below the 21 percent estimated in a state survey in April. But that number was based on people recruited at supermarkets, and so the results may have been biased toward people out shopping during a pandemic — often the young, who have been less affected.
The global fatality rates could still change. With one or two exceptions, like Iran and Ecuador, the pandemic first struck wealthier countries in Asia, Western Europe and North America where advanced medical care was available.The global fatality rates could still change. With one or two exceptions, like Iran and Ecuador, the pandemic first struck wealthier countries in Asia, Western Europe and North America where advanced medical care was available.
Now it is spreading widely in India, Brazil, Mexico, Nigeria and other countries where millions are crowded into slums, lockdowns have been relatively brief and hospitals have few resources.Now it is spreading widely in India, Brazil, Mexico, Nigeria and other countries where millions are crowded into slums, lockdowns have been relatively brief and hospitals have few resources.
But the death rates may also shift in wealthier northern countries as winter approaches. Most of the spread of the virus in Europe and North America has taken place during mild or warm weather in the spring and summer.But the death rates may also shift in wealthier northern countries as winter approaches. Most of the spread of the virus in Europe and North America has taken place during mild or warm weather in the spring and summer.
Many experts fear that infections and deaths will shoot up in the fall as colder weather forces people indoors, where they are more likely to infect one another. Discipline about wearing masks and avoiding breathing on one another will be even more important then.Many experts fear that infections and deaths will shoot up in the fall as colder weather forces people indoors, where they are more likely to infect one another. Discipline about wearing masks and avoiding breathing on one another will be even more important then.
In each of the eight influenza pandemics to hit the United States since 1763, a relatively mild first wave — no matter what time of year it arrived — was followed by a larger, much more lethal wave a few months later, noted Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.In each of the eight influenza pandemics to hit the United States since 1763, a relatively mild first wave — no matter what time of year it arrived — was followed by a larger, much more lethal wave a few months later, noted Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
More than a third of all the people killed by the Spanish flu, which lasted from March 1918 to late 1920, died in the short stretch between September and December 1918 — about six months after a first, relatively mild version of what may have been the same virus broke out in western Kansas.More than a third of all the people killed by the Spanish flu, which lasted from March 1918 to late 1920, died in the short stretch between September and December 1918 — about six months after a first, relatively mild version of what may have been the same virus broke out in western Kansas.
“We will go much higher in the next 12 to 18 months,” Dr. Osterholm said. Because this is a coronavirus, not influenza, it may not follow the same pattern, but it is “a much more efficient transmitter than influenza.”“We will go much higher in the next 12 to 18 months,” Dr. Osterholm said. Because this is a coronavirus, not influenza, it may not follow the same pattern, but it is “a much more efficient transmitter than influenza.”