While Covid-19 was the third leading cause of death in 2020 and 2021 overall, for some age groups it was the leading cause of death, according to a study published in JAMA Internal Medicine.

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Covid-19 was the third leading cause of death in 2020 and 2021

For the study, researchers reviewed death certificate data from March 2020 through October 2021. They found that Covid-19 accounted for 697,000 deaths during that period, making it the third leading cause of death behind heart disease—the leading cause of death—and cancer, both of which combined for a total of 2.15 million deaths.

Notably, the researchers found that Covid-19 was the leading cause of death among people ages 45-54 during the time period—accounting for 16.8% of all deaths in that age group—and the second leading cause of death among people ages 35-44.

Meanwhile, among those ages 85 and older, Covid-19 death rates dropped slightly during the study period. In 2020, Covid-19 was the second leading cause of death among those 85 and older but dropped to the third leading cause of death in 2021, likely because of targeted vaccination efforts among those in that age group.

What the future of the pandemic may hold

While Covid-19 is still killing around 360 people a day, death rates have dropped significantly since the fall and winter, leading Dan Kaul, an infectious diseases specialist at the University of Michigan Medical Center, to feel "cautiously good right now."

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"For the first time that I can remember, pretty much since it started, we don't have any [Covid-19] patients in the ICU," he said.

While Covid-19 death rates are roughly around where they were last summer, case rates right now are significantly higher, sitting at around 109,000 new Covid-19 cases per day compared with fewer than 20,000 a day last year, the Associated Press reports.

Case rates are higher, but the risk of death is lower, which according to David Dowdy, an infectious disease epidemiologist at Johns Hopkins Bloomberg School of Public Health, is because, "[W]e're now at a point that everyone's immune system has seen either the virus or the vaccine two or three times by now," he said. "Over time, the body learns not to overreact when it sees this virus."

However, experts warn that things could change quickly. Peter Hotez, an infectious disease specialist at the Baylor College of Medicine, said it would be wise to assume a new variant will arrive later this summer. "And then another late fall-winter wave," he said.

Currently, the BA.5 subvariant of omicron accounts for the majority of Covid-19 cases in the United States, making up 53.6% of all cases, according to CDC, while the BA.4 subvariant accounts for 16.5%.

Given that BA.5 is now the dominant strain in the United States, "its behavior will determine our fate for the next few months, until it either burns itself out by infecting so many people or is replaced by a variant that's even better at infecting people," said Bob Wachter, chair of medicine at the University of California, San Francisco.

Wachter stressed that vaccines and booster shots "remain hugely valuable in preventing severe cases" of Covid-19 that could lead to hospitalization or death.

Similarly, Celine Gounder, an infectious disease expert at New York University, emphasized that people shouldn't wait for updated vaccines to get their booster shots.

"The updated vaccines won't be available until October at the earliest," she said. "That's 4+ months away. That's a big window of risk." (Bettelheim, Axios, 7/6; Weixel, The Hill, 7/5; Schoonover, Becker's Hospital Review, 7/5; Johnson, Associated Press, 7/3; Sullivan, The Hill, 7/5; Fagone, San Francisco Chronicle, 7/5)