One model projects a sobering outlook for rising COVID-19 cases in the US and Mass. as Omicron surges

People lined up to receive test kits to detect COVID-19 as they are distributed in the Lower East Side neighborhood in the Manhattan borough of New York on Thursday.Craig Ruttle/Associated Press

An updated projection model shows COVID-19 infections fueled by the Omicron variant are expected to surge dramatically in the coming weeks in the United States and across the world, though it is less likely to result in severe outcomes like hospitalizations and deaths than the Delta variant.

The Institute for Health Metrics and Evaluation at the University of Washington estimated that over the course of the next three months, there could be 3 billion new COVID-19 infections worldwide.

According to the model, the United States is in the initial ascent of an incline that could peak in late January at more than 2.8 million new daily infections.

It also provided a sobering outlook for how Massachusetts could fare in the upcoming weeks, with researchers estimating a potential high of more than 87,000 cases per day at the end of January.

Dr. Christopher Murray, the institute’s associate director, said in a blog post that because a significant number of the cases will be asymptomatic and people won’t seek tests, the reported number of confirmed cases could be significantly less, reaching 400,000 new daily cases in the US at its peak.

The Omicron variant will result in fewer hospitalizations and deaths in what is a “shred of good news” amid a “huge increase” of global COVID infections, Murray said in the post. In the United States, researchers predicted that the number of hospitalizations will appear similar to last year’s winter peak, but potentially higher than those recorded in early September. The number of deaths could be lower than both the levels in September and last year’s winter peak, according to the model.

“Because of the greatly reduced infection-hospitalization rate, and the even more-reduced infection-fatality rate, this massive surge of infections and cases will translate into a smaller surge in hospitalizations than either the Delta wave or the winter peak last winter at the global level,” Murray said.

Dr. Jagpreet Chhatwal, an assistant professor at Harvard Medical School and the associate director of Massachusetts General Hospital’s Institute for Technology Assessment, which also projects COVID-19 metrics, cautioned that trying to predict what may happen with the virus in the weeks ahead is “highly uncertain.”

New information emerges about COVID-19 every day, and while Omicron appears to be more transmissible than other variants, a complete picture of the variant is not yet clear. Additionally, human behavior factors into the how COVID-19 metrics will play out in real life, and those actions are impossible to predict.

However, the IMHE model’s projections are “not unreasonable,” Chhatwal said, but may be “on the higher side.” He wasn’t surprised by the degree to which infections in the US could potentially surge, he added.

Omicron has arrived at the “worst timing possible,” Chhatwal said, as people prepare to travel and see loved ones for the holidays, colder weather pushes gatherings inside where the virus can transmit more easily, and immunity from vaccines wanes, factors that will contribute to rising COVID infections over the next few months.

The IHME model accounts for different scenarios based on Omicron’s severity and levels of mask-wearing and the population receiving booster vaccinations.

Dr. Shira Doron, an infectious disease physician and hospital epidemiologist at Tufts Medical Center, also cautioned that COVID-19 has proved particularly hard to predict throughout the pandemic, including the way the virus functions during different seasons.

However, what stood out to Doron about the University of Washington model was the similarity between the projected number of COVID-19 infections and the estimated number of cases if 100 percent of the population has received a third dose. The fact that projected cases didn’t drop when factoring in the additional layer of protection boosters provide highlighted Omicron’s ability to evade immunity the vaccine provides, Doron said.

For example, in Massachusetts, at the projected peak on Jan. 25, the number of cases is about 87,800. The number of cases projected when considering booster shots stood at about 84,740. By the institute’s model, 80 percent of people wearing masks provided a greater degree of protection than boosters did. As with the national and global numbers, the number of cases reported by the state during this time is likely to be lower than what projections because of asymptomatic cases and people who don’t seek testing.

“The interesting thing about the model is how little they seem to think the vaccination will make a difference,” Doron said. “We need people to get their first doses and their second doses so much more than we need people to get their third doses, but even two doses of an mRNA vaccine aren’t going to protect you from getting infected with Omicron. But they will really protect you from getting hospitalized and dying from Omicron.”

“We need to shift the way we speak about these vaccines, and their purpose to being to protect you from the worst complications, not from any infections,” she added.

Early studies have shown that the Omicron variant can evade some protection provided by vaccines, and public health experts have warned of rising numbers of breakthrough cases as the variant becomes more widespread. Early data from the National Institute of Allergy and Infectious Diseases found that Omicron can evade protection from the vaccines, but people who had two doses of an mRNA vaccine saw increased protection against the variant after they received a booster shot.

Doron said she is “slowly and reluctantly becoming convinced” that the number of cases that result in hospitalizations and the number of hospitalizations that result in deaths are lower with the Omicron variant than Delta. However, even if that’s the case, the sheer volume of cases depicted in the IHME model would be high enough to counteract the benefit that comes from Omicron potentially being less lethal.

“You can still have more deaths in the Omicron wave, easily, because it’s more contagious, or just because it infects more people,” Doron said. “You can still, obviously, easily overwhelm the health care system, and that means deaths that aren’t even due to COVID because there’s no medical care. It’s better than being equally or more deadly, but it doesn’t necessarily reassure me that we’re not going to see a lot of excess death in the next month.”

COVID cases are already surging in Massachusetts. On Thursday, the state broke a record for the second day in a row for the highest number of confirmed COVID-19 cases reported in a single day.

“People were not expecting this,” Chhatwal said of the surge. “Two months earlier, things were going down with vaccinations kicking in. We all were very hopeful that we were at the tail of it. But this Omicron has thrown a new surprise in this game.”