Is COVID more dangerous than driving a car? How do scientists analyze COVID risks?

The worker inspects people who came to the COVID-19 test site in Baltimore on December 30, 2021.  (Al Drago / The New York Times)

The worker inspects people who came to the COVID-19 test site in Baltimore on December 30, 2021. (Al Drago / The New York Times)

Whether we like it or not, the pandemic’s “choose your own adventure” era is approaching.

Mask mandates have dropped. Some free trial sites have been blocked. Although parts of the United States are still trying to suppress the pandemic collectively, they have diverted attention from public recommendations.

Now, although the number of cases is on the rise again and no more infections are reported, it is up to individual Americans to decide how much they and their neighbors are at risk from the coronavirus and what they will do about it.

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The threat posed by COVID to many people has declined sharply in the two years since the pandemic. Vaccines reduce the risk of hospitalization or death. Strong new antiviral pills can protect susceptible people from getting worse.

But not all Americans can rely on the same defense. Millions of people with weakened immune systems are unable to take full advantage of vaccines. Two-thirds of Americans and more than a third of those 65 and older did not receive critical safety from the most disturbing proportions of blacks and Hispanics. And patients who are poor or live far from doctors and pharmacies face severe barriers to taking antiviral pills.

These vulnerabilities made it difficult to calculate the risks posed by the virus. The latest proposal by federal health workers to stop most Americans from wearing masks because of the small number of hospitalizations has caused confusion in some quarters as to whether the risk of infection has changed, scientists said.

“We’re doing a really terrible job of delivering the risks,” said Katelyn Jetelina, a public health researcher at the University of Texas Center for Health Sciences in Houston. I think people raise their hands in the air and say, “Shoot.” They are desperate for some kind of leadership. “

To fill this gap, scientists are rethinking how to discuss COVID risks. Some have learned when people can take off their masks indoors if the goal is not only to prevent overcrowding in hospitals, but also to protect people with weakened immune systems.

Others are working on tools to compare the risk of infection with the dangers of different activities, such as the average death of an unvaccinated person 65 or older from heroin is approximately the same as the risk of death from omiron infection. For a period of 18 months.

But how people perceive risk is subjective; two people do not have the same feeling about the chance of dying from a year and a half of heroin use (according to one estimate, about 3%).

In addition, many scientists are concerned that this latest phase of the pandemic, especially when COVID control tools are beyond the reach of some Americans, is putting too much burden on individuals to choose to keep themselves and others safe.

Anne Sosin, who studied health equality at Dartmouth College, said, “Although we don’t want to believe it, we still need a community-based approach to protect the pandemic, especially those who can’t fully benefit from the pandemic.” vaccination. ”

Collective Metrics

Although COVID is far from America’s only health threat, it remains one of the most important. In March, even though deaths from the first omicron increase decreased, the virus was still the only leading cause of death in the United States after heart disease and cancer, the third leading cause of death.

In general, more Americans die than usual, which is a sign of a large number of viruses. As of late February, 7% more Americans were dying than expected in previous years – in contrast to Western European countries such as the United Kingdom, where overall deaths have been lower than expected in recent years.

Scientists say it is one of the most important measures for people trying to measure the risks of how much virus is circulating in the population. Although many Americans now have a large difference in the number of true infections because they are tested at home or not tested at all, this remains true.

The Centers for Disease Control and Prevention, despite many cases of abduction, now places much of the Northeast at “high” levels of viral transmission. Although the number of jobs in some parts of the region is much lower than in winter, it is approaching the peak rate of growth of the autumn delta variant.

The rest of the country has what the CDC describes as “average” transmission levels.

Scientists say the amount of virus in circulation is critical because it dictates the likelihood that someone will come in contact with the virus, which in turn will lead to a bad outcome.

Scientists say that’s part of what makes COVID so different from the flu: Coronavirus can infect more people at the same time, and while people are more likely to catch it, the chances of an overall bad outcome increase.

Lucy D’Agostino McGowan, a biostatistics specialist at Wake Forest University, said, “We’ve never seen the spread of the flu – how much it’s in society – in the numbers we see with COVID.”

COVID against driving

Scientists say that two years after the pandemic, the coronavirus remains relatively new, and its long-term effects are so unpredictable that it is difficult to measure the risk posed by the infection.

Some unknown number of infected people will develop COVID over a long period of time and severely weaken them. And the risk of contracting COVID extends to others who are potentially ill and may be exposed as a result.

However, some public health researchers, who have more immunity than ever before, have tried to make risk estimates more accessible by comparing the virus to everyday threats.

The comparisons are particularly complex in the United States: the country does not conduct randomized cleansing studies to assess infection levels, making it difficult to know how many infected people have died.

Jetelina, who published a series of comparisons in the Bulletin of Your Local Epidemiologist, said the exercise highlighted how difficult it is to calculate risk for everyone, including public health researchers.

For example, he estimated that a moderately vaccinated and amplified person at least 65 years of age had a slightly higher risk of dying from COVID infection in 2011 than a year of military service in Afghanistan. He used the standard. a unit of risk known as a micromort, which represents a chance of one death per million.

However, his calculations, however crude, did not cover undiagnosed and generally milder infections, but only reported cases. And he looked at a weekly report in January, ignoring the delay between cases and deaths. Each of these variables could change risk estimates.

“All of these nuances underscore how difficult it is for individuals to calculate risk,” he said. “Epidemiologists also have a problem with that.”

He found that the risk of death after COVID infection for children under the age of 5 was the same as the risk for mothers who died during childbirth in the United States. However, this comparison highlights other difficulties in describing risk: Average numbers can hide large differences between groups. For example, black women are about three times more likely to die during childbirth than white women, reflecting some of the differences in the quality of health care and racial bias in the health care system.

Cameron Byerley, an associate professor of mathematics at Georgia University, has created an online tool called COVID-Taser, which allows people to adjust their age, vaccination status and health status to predict the risks of the virus. His team used previous estimates of the proportion of infections that led to poor outcomes during the pandemic.

His research has shown that people have difficulty interpreting percentages, Byerley said. He recalled that his 69-year-old mother-in-law was not sure if she was worried before the pandemic after a news program said people her age had a 10% risk of dying from the infection.

Byerley asked his mother-in-law to imagine that one out of every 10 times he used the toilet in a day died. “Oh, 10% is awful,” he recalled his mother-in-law saying.

Byerley’s calculations, for example, show that an average 40-year-old man who was vaccinated six months ago has a chance of being hospitalized after an infection, just as he died in a car accident while traveling between 170 countries. . (Newer vaccinations provide better protection than older ones, making these predictions more difficult.)

People with weakened immune systems have higher risks. Byerley estimates that a 61-year-old who has not been vaccinated with an organ transplant is three times more likely to die from an infection after five years after being diagnosed with stage 1 breast cancer. And this transplant recipient is twice as likely to die from COVID as he climbed Mount Everest.

Given the most sensitive people, Dr. Brigham and Women’s Hospital Emergency Physician in Boston. Jeremy Faust set out last month to determine how low people would go to stop masking indoors without endangering people with severely weakened immune systems. systems.

He imagined a hypothetical man who did not benefit from vaccinations, wore a good mask, took hard-to-obtain prophylactic drugs, attended regular meetings and went shopping, but did not work in person. He aimed to keep the susceptibility of infected people below 1% for four months.

To reach that point, he found that the country would have to continue to disguise itself indoors until the weekly infection rate fell below 50 per 100,000 people – a tougher restriction than the CDC currently uses, but nonetheless a criterion for targeting, he said. .

“If you just say, ‘We’ll take off the masks when things get better,’ which I hope is true, but it’s not really helpful because people don’t know what ‘better’ means,” Faust said.

Layered Protections

The end of collective efforts to reduce the level of infection for people with immunodeficiency has been frustrating.

Marney White, a professor of public health at Yale University who has a weakened immune system, said: He said families in the local school district encouraged each other not to report each other’s COVID incidents. “It is impossible to calculate the risk in these situations,” he said.

White House COVID Response Coordinator Dr. Ashish K. Jha said the administration has helped reduce people’s risks by making it easier to get quick tests and masks and working with clinics to prescribe antiviral pills quickly. He said better communication is needed for people with weakened immune systems to spread prophylactic drugs.

“We need a system that can easily deliver therapies to them,” he said. “It’s a big responsibility of the government.”

Scientists say that better preparation for current and future growth can make people more manageable, even if it doesn’t eliminate risks. They said the government could help people make choices with less fear of disaster by ventilating indoors, guaranteeing paid sick leave, delivering boosters to people’s doors and making treatment easier.

David Dowdy, a public health researcher at Johns Hopkins University, said, “We need to create an infrastructure that allows us to respond quickly when we have the next wave.”

“We need to teach people that when these waves hit, there are some things we need to see,” he said, like applying short-term mask mandates. “Then you can live your life for that possibility – but not for fear that it could happen at any moment.”

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