The United States’ leading authority on infectious disease expressed hope in April that no more than 60,000 people in the country would die from the coronavirus. A revered research center predicted a few weeks later that the figure would be just over 70,000 people by early August. When the number of deaths shot up in May, President Trump said that anywhere between 75,000 and 100,000 people could die.
On Wednesday, the nation’s death toll surpassed 150,000.
That the figure, based on a New York Times database, has soared so soon and so far beyond those estimates illustrates how difficult it can be to accurately forecast the spread of the virus, or the way citizens and politicians will respond to it.
“The aspect which is really impossible to predict is human behavior,” said Virginia Pitzer, a professor of epidemiology at Yale. “To what extent are people going to socially distance themselves? To what extent are politics going to influence whether you wear a mask? All of these factors are impossible to factor in.”
Americans have rarely been as hungry for scientific predictions as they have been this year. Charts of virus case counts fill social media feeds; epidemiologists are all over television; Dr. Anthony S. Fauci has become a household name.
But the statistical modelers who were trying to predict the spread of a new virus began with very little solid data, experts said, so it was no surprise that they have had to repeatedly revise their projections. The revisions have generally been in one direction: up.
As of Wednesday evening, at least 150,909 people were known to have died of the virus in the United States, out of more than 4.4 million reported infections. And even these figures are likely to be undercounts, experts say.
The Centers for Disease Control and Prevention estimate that in some regions the number of people who have been infected could be two to 13 times higher than the tallies of reported cases. Experts have said the official death toll probably omits many people whose deaths were virus-related, especially early in the pandemic. And more people will die each day as long as the virus continues to spread.
Weekly averages of reported deaths in the United States had fallen substantially since an early peak in mid-April, when the national death toll was driven largely by a catastrophic surge in New York State. But deaths began to climb again this month, and the nation is now reporting about 1,000 deaths a day.
The current toll is being felt much more widely across many states, especially in the South, while New York is down to reporting an average of 16 deaths a day. Nearly 2,200 deaths have been reported in the past week in Texas, the state with the highest recent death toll relative to its population, followed by Arizona and South Carolina. Florida broke its daily record again on Wednesday, reporting 216 fatalities and bringing the state’s overall total to 6,332.
“The mortality is going to march in lockstep with our transmission,” said Dr. Sarah Fortune, the chair of immunology and infectious diseases at the T.H. Chan School of Public Health at Harvard.
Exactly what percentage of people who get the virus die from it is not yet clear. The World Health Organization’s chief scientist, Dr. Soumya Swaminathan, said last month that it was likely to be about 0.6 percent. If that rate proves accurate, it would mean a vast majority of infections in the United States have gone unreported.
Dr. Fortune estimated that a mortality rate of 0.5 percent of all coronavirus cases would be a “best-case scenario,” but that the death rate could range up to 2 percent of cases, depending on how much the virus reaches into the highest-risk environments, like nursing homes.
“We have to do better in terms of limiting transmission,” Dr. Fortune said. “We have this terrible death toll because we have done a lousy job at limiting transmission.”
The Coronavirus Outbreak ›
Frequently Asked Questions
Updated July 27, 2020
Should I refinance my mortgage?
- It could be a good idea, because mortgage rates have never been lower. Refinancing requests have pushed mortgage applications to some of the highest levels since 2008, so be prepared to get in line. But defaults are also up, so if you’re thinking about buying a home, be aware that some lenders have tightened their standards.
What is school going to look like in September?
- It is unlikely that many schools will return to a normal schedule this fall, requiring the grind of online learning, makeshift child care and stunted workdays to continue. California’s two largest public school districts — Los Angeles and San Diego — said on July 13, that instruction will be remote-only in the fall, citing concerns that surging coronavirus infections in their areas pose too dire a risk for students and teachers. Together, the two districts enroll some 825,000 students. They are the largest in the country so far to abandon plans for even a partial physical return to classrooms when they reopen in August. For other districts, the solution won’t be an all-or-nothing approach. Many systems, including the nation’s largest, New York City, are devising hybrid plans that involve spending some days in classrooms and other days online. There’s no national policy on this yet, so check with your municipal school system regularly to see what is happening in your community.
Is the coronavirus airborne?
- 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.
What are the symptoms of coronavirus?
- 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.
Does asymptomatic transmission of Covid-19 happen?
- 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.
How well Americans will adhere to measures meant to limit the spread of the virus has been one of the hardest things to predict, experts said, and may be partially to blame for the underestimates.
Dr. Fauci and Dr. Deborah L. Birx, the Trump administration’s coronavirus response coordinator, estimated in March that the virus could kill between 100,000 and 240,000 people in the United States, even with preventive measures. In early April, Dr. Fauci said on the “Today” show that he thought deaths may never reach 100,000.
“Models are really only as good as the assumptions that you put into the model, but when you start to see real data, you can modify that model, and the real data are telling us that it is highly likely that we’re having a definite positive effect,” Dr. Fauci said on the show, later adding: “It looks more like the 60,000 than the 100,000 to 200,000. But having said that, we’d better be careful that we don’t say, ‘OK, we’re doing so well, we can pull back.’”
By May 1, several states were reopening gyms, salons, restaurants and other businesses. Mr. Trump, who has given a wide range of predictions for the ultimate death count, said on May 3 that the virus might end up killing 100,000 people, after saying for much of April that the virus would not kill more than 75,000.
The next day, the Institute for Health Metrics and Evaluation, whose model is closely watched by the White House, increased its own projection, warning that there would likely be about 135,000 deaths by early August. The institute’s model, which includes a wide range of possible scenarios, now projects about 220,000 deaths by November.
Adding to the difficulty of predicting human behavior, Professor Pitzer said, is that public policy can be influenced by the models: seeing a forecast may prompt officials to take actions that make the forecast less likely to come true.
“Models are useful for playing out scenarios, but they’re not really meant to be accurate in generating long-term predictions,” she said. “They can be good at short-term forecasting — what might happen in the next couple of weeks. But longer term, knowing exactly what the trajectory of the epidemic will be — there are just too many variables.”
Sarah Mervosh contributed reporting.