A masked-up man walks a waterfront path in Portland on Thursday Jan 14, 2021. Credit: Troy R. Bennett / BDN

An often-cited predictive model suggests the coronavirus pandemic in Maine may continue to worsen during a national decline as the state manages a vaccine rollout that has been slower nationally than officials hoped and girds for a more contagious strain of the virus.

Maine set records last week with three consecutive days of more than 800 virus cases. Though case totals dropped slightly this week, two major hospitals saw record hospitalizations and the state’s top health official said it was premature to say whether cases have flattened after a post-holiday surge.

Researchers at the University of Washington’s Institute for Health Metrics and Evaluation say virus cases in the U.S. appear to have declined over the past two weeks after increasing steadily throughout the fall and into winter. But their model indicates cases and deaths in Maine could increase into February depending on the rates of vaccinations and mask-wearing.

Other metrics have indicated reasons for optimism in Maine in the last week. Hospitalizations have dropped slightly since last week, when a record 207 people were hospitalized with the virus. The seven-day positivity rate for viral and antigen tests dropped below 5 percent this week for the first time since late December.

But Nirav Shah, director of the Maine Center for Disease Control and Prevention, said Thursday that the decline was in part a function of an increase in viral testing, which would help detect more of the virus but may not reflect a decline in its spread. More than 87,000 tests were performed over the past week, up from 64,000 in the first week of January, the state said.

“There are some signs for optimism because testing is expanding, giving us a better view into what’s happening, but there simultaneously remain causes for concern,” Shah said.

He remained worried about hospitalizations, particularly as the number of patients in critical care units set a new record early this week as overall hospitalization numbers declined. Different parts of the state saw opposing patterns, with hospitalizations declining in the Bangor area but setting records at hospitals in Portland and Lewiston. The IHME model predicts an increase in daily hospitalizations and deaths for several more weeks after cases start declining.

Models are sensitive to a number of factors including changes in people’s behavior or the virus itself, and the IHME model and others missed at times early on in the pandemic amid scientific disagreement about how contagious the virus was and the effects of mitigation measures. The IHME model has variants based on state restrictions and the rate of vaccinations, and suggests infections in Maine would decline more quickly if the state achieved universal mask-wearing.

Masks have been mandatory in Maine for most of the pandemic, though the survey data the model relies on suggests they are only used about 80 percent of the time. But significant changes in personal behavior are unlikely at this point in the pandemic, said Robert Horsburgh, an epidemiology professor at Boston University, and the effects would not be immediate even if people did adopt new habits.

“It takes time to slow it down,” Horsburgh said. “You wouldn’t expect heightened restrictions to have any effect for two weeks.”

One other factor adding unpredictability to models is the potential for the introduction of a more contagious strain of the virus. A strain first detected in the United Kingdom that researchers say is between 40 percent and 50 percent more transmissible than other iterations has now been reported in nearly two dozen U.S. states, including Massachusetts earlier this week. No cases have been confirmed in Maine.

Testing for the new strain goes on at the Jackson Laboratory, where researchers have sequenced about 2 percent of positive virus samples in Maine — a share that may seem small but ranks better than all but a handful of U.S. states. The lab is aiming to reach 5 percent, said lead researcher Ryan Tewhey.

Tewhey anticipate the new variant “eventually will” arrive in Maine and said the higher transmissibility is a concern, noting the strain became dominant in the United Kingdom within a few months, though he added that it is not more lethal than other versions of the virus.

Researchers believe new strains are still covered by the vaccine, and widespread inoculations could lessen concerns about transmission if the more contagious version is detected here. But the state remains far from that for now, with about 5.5 percent of Mainers having received at least one dose of the vaccine while 1.3 percent have received both doses. That is still one of the highest marks in the nation among states, according to a Bloomberg News tracker.

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