AUGUSTA — State health epidemiologists are using complex models predicting coronavirus infections, hospitalizations and deaths as they work to prevent widespread transmission and prepare for the worst.

For the public, the questions are simple: How long will this last? How many people are going to die? When will we hit the peak of the infection “curve” or learn whether physical distancing measures and business closures have been effective?

But for epidemiologists and other public health experts, there’s nothing simple about trying to predict the trajectory the deadly virus will take.

Dr. Nirav Shah, director of the Maine Center for Disease Control and Prevention, said his team has been closely following several models as the agency keeps track of the availability of hospital beds and ventilators as well as supplies of personal protective gear.

One report by University of Washington researchers forecasts that Maine could experience 334 deaths by early August, with the peak of COVID-19 infections in Maine occurring around April 24. Shah said Maine epidemiologists use the Washington work, and that of Johns Hopkins University in Maryland, which has emerged as a leading tracker of COVID-19 cases worldwide, and modeling by Imperial College of London.

Shah, who is reluctant to discuss details of the projections, said the staff at the Maine CDC relies on the various modeling systems to gear up for a range of potential situations, given the unpredictable nature of this new, highly infectious disease.

“The goal is to come up with lower-bound parameters and higher-bound parameters and make sure we have accounted for all of the scenarios in between,” Shah said Monday during his daily briefing with the media. “But recognize that every model is only as good as the assumptions you put into it, and those assumptions, they may or may not reflect reality.”

Although imprecise by their nature, the forward-looking models are having an impact on government leaders and how seriously they are taking the coronavirus threat.

It was a mid-March report from Imperial College of London that reportedly prompted President Trump as well as his counterpart in the United Kingdom, Prime Minster Boris Johnson, to announce new “social distancing” measures and guidelines. Imperial College’s report warned the virus could kill 2.2 million and 510,000 people, respectively, in the two countries unless more aggressive actions were taken.

Similarly, Trump extended the federal government’s voluntary social distancing guidelines through April 30 after Dr. Anthony Fauci, the nation’s top infectious disease expert, projected between 100,000 and 200,000 deaths. Just last week, Trump had been suggesting that he could loosen those guidelines – which have influenced state-level decisions – in hopes of “reopening” the U.S. economy by the April 12 Easter holiday.

Maine had 275 confirmed cases of the COVID-19 disease caused by the coronavirus as of Monday, according to the Maine CDC. Shah reiterated that the confirmed cases figure only reflects “the tip of the iceberg” because many people may be infected but are not exhibiting symptoms or have yet to be tested.

Unlike with well-known infectious diseases such as tuberculosis or measles, it’s still unclear how much of the iceberg remains hidden underwater, he said.

When the Maine CDC conducts its planning, staff build different models based on the assumption that they are only seeing 10 percent of cases and another model that assumes the confirmed cases represent 50 percent of infections.

Officials in some other states have discussed projections, such as in Connecticut, where the state’s top epidemiologist suggested earlier this month that 10 to 20 percent of the population could become infected this spring. New York Gov. Andrew Cuomo warned over the weekend that “I don’t see how you look at those numbers and conclude anything less than thousands of people will pass away” in his state.

Shah, in contrast, rarely discusses or endorses specific projections and did not directly answer a question about how many coronavirus infections there are in Maine today.

“So that’s why when we do our modeling, we use a range of assumptions,” Shah said. “That’s how modeling is done. It’s not intended to provide THE answer, it is intended to provide us with a broad range of answers so we can think about how our planning should go.”

To date, the administration of Gov. Janet Mills has been more reserved than some of her counterparts in other New England and northeastern states when it comes to issuing state mandates to control the spread of COVID-19.

For instance, while cities such as Portland and South Portland have issued “stay at home” orders to residents, Mills has not ordered such restrictions statewide.

But Shah said the governor carefully considers the local modeling conducted by Maine CDC as well as projections prepared by groups outside of the state when working with Shah and other health officials on the state’s response.

“The governor believes the modeling underscores the critical necessity for continued physical distancing,” Mills spokeswoman Lindsay Crete said in a statement on Monday.” While she has closed the public-facing operations of nonessential businesses and mandated that there be no gatherings of more than 10 people, the governor is considering additional restrictions in order to further enforce physical distancing measures.”

“Governor Mills continues to urge Maine people to take serious the threat of this virus, to practice physical distancing, to stay home whenever possible, and to leave home only when necessary,” Crete said. “Doing so will save lives.”

 


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