番茄社区

The U.S. probably won't see a major surge in COVID deaths this winter, according to from the Institute for Health Metrics and Evaluation (IHME) at the University of Washington in Seattle.

By Feb. 1, 2023, daily deaths are projected to be at a high point of 335, which pales in comparison to the approximate 2,500 daily deaths seen during the Omicron surge around the same time last year, according to a .

The report estimates the COVID-19 infection-fatality rate (IFR) to be below 0.2% as of October 17.

"Many people have been exposed to COVID-19, either through infection or through vaccination, [so we don't expect] a high hospitalization rate and high mortality rate," Ali Mokdad, PhD, a professor at IHME and chief strategy officer for population health at the University of Washington, told 番茄社区. "We will see a little bit of a rise, but it will not be as high as what we have seen in the past."

Also contributing to that flattening of the deaths curve is the fact that current and emerging variants appear less severe and unable to thwart humoral and cellular immunity -- though Mokdad warned that the appearance of a new variant that is more severe and immune-evasive could change those predictions. Nonetheless, he said, the probability of that happening is small.

Still, the U.S. will see some 30,000 deaths and globally there will be about 250,000 deaths by February 1, though this includes deaths where the virus was present but didn't necessarily cause or contribute to the deaths, according to the policy brief.

"Our inability to distinguish effectively between hospital admissions and deaths due to COVID-19 as compared to with COVID-19 hampers our understanding of the true impact of COVID-19 now," the policy brief stated.

Shaun Truelove, PhD, an epidemiologist at Johns Hopkins Bloomberg School of Public Health who works on its , said his team has modeled several different scenarios for COVID this winter. The worst-case -- a powerful new variant coming along, as Mokdad noted -- would bring a peak of 1,000 deaths per day in this winter's surge.

"I'd like to think we have this rosy future, but I am skeptical still," Truelove told 番茄社区. "Looking at the number in February is fine, but more importantly, we need to think about this much sooner timeframe where we start to see increases in [cases] in the U.S., and those increases will lead to more deaths just by the nature of numbers."

As for infections, there's also unlikely to be a dramatic surge like the one caused by Omicron last winter, according to the report. At the beginning of February, the U.S. will see about 1 million infections per day, far lower than the estimated 5 million daily cases during Omicron's peak last year.

These cases, however, won't be reported, because people will be asymptomatic, mildly symptomatic, or won't report their at-home tests results to local health officials, Mokdad said. Currently, only about 5% of cases are being reported to health officials, according to the policy brief.

Daily hospitalizations will reach 26,000 in the U.S. by February 1, though no states are expected to have high or extreme stress on hospital beds or ICU capacity, according to IHME.

The reason for this hopeful picture comes down to immunity, Mokdad said. IHME estimates that 95% of people in the U.S. have been infected by the virus to date -- and that's not even counting vaccinated immunity, he said.

As part of that, about 62% of people in the U.S. have been infected with Omicron sublineages BA.1 and BA.2, and about 60% have been infected with BA.5, giving a large swath of the population recent immune memory that could help stave off infection.

"About 5 months after an infection or a vaccine, your immunity goes down," Mokdad said. "But the good news is that both infection and the vaccine give your B and T cells something to remember" to help fight the virus.

Lessons from around the world have helped IHME piece together what's likely to happen in the U.S. this winter. In Singapore, an Omicron variant called XBB caused a recent surge in infections, but that didn't translate to a higher hospitalization rate in this highly vaccinated country.

XBB showed almost no immune escape from a recent BA.5 infection, which will limit its impact globally, according to the report. It also appears to be slightly less severe than BA.5, Mokdad said.

In Germany, on the other hand, a recent surge did lead to an uptick in hospitalizations. Researchers still aren't sure exactly what's behind that surge, as there are many variants circulating in that country, including BA.5. Oktoberfest celebrations likely played some role, as people who hadn't participated in the festival in the past few years finally returned, though they were quite susceptible to the virus, Mokdad said.

The German surge seems to have peaked for now, but Mokdad said what happened there could happen in other places in Europe, and could eventually hit the U.S. -- though we are in "a better position than the Europeans to handle the next wave" because of our immunity wall.

What concerns Mokdad is China. There have been "mixed signals" from the country as to whether it will continue to aggressively pursue its zero-COVID policy.

If it decides against continuing that policy, there will be a "dramatic effect on infections, hospitalizations, and deaths," according to the report. The country's older population is less vaccinated than its younger population, and the vaccine itself isn't as protective as the mRNA shots used in the west, he said.

Though the U.S. won't see a similar fate, Mokdad said it's still important to protect vulnerable populations, especially older adults. He mentioned his 82-year-old mother, who has chronic health conditions. "We all have family members at high risk, so we need to be very careful," he said.

He added that IHME modeling shows that if 80% of the U.S. population wears a mask, daily deaths this winter will be cut by a third.

Boosters are also critically important, he said. He had four doses of vaccine before he was infected with Omicron earlier this year. He had minor symptoms that he thought were allergies, and he only tested because he wanted to go to the hospital where his wife was having a procedure.

When he discovered his positive test, he quarantined and didn't infect any other members of his household.

"Getting the booster now will protect against hospitalization," he said, adding that there's also the potential for a double threat of COVID and flu this winter.

"I wouldn't say we're in a good position, because our hospitals have been under a lot of pressure," Mokdad said. "It's possible we'll have a bad flu season, so the combination of the two could still overwhelm hospitals, especially in areas where you have high-risk people."

Comment