A woman receives at-home Covid-19 test kits after waiting in a long line that snakes multiple times around the Shaw Library in Washington, Wednesday, Dec. 22, 2021. Credit: Andrew Harnik/AP

The number of Mainers carrying and spreading the coronavirus is likely even higher than official case counts show, even as the state continues to see near record-high levels of new infections.

While public health experts are nearly unanimous that at-home tests are key to fighting the coronavirus’ spread, they’re also part of the reason for the undercount, as those taking at-home tests seldom report their results to the state. In addition, many people infected with the virus are not getting tested, whether because tests are too expensive, they’re not showing symptoms, or they believe in coronavirus misinformation.

Public health officials have always known that their data didn’t portray every case of an illness during past pandemics and epidemics, Maine Center for Disease Control and Prevention Director Nirav Shah said. The coronavirus pandemic is no different. 

A woman holds two boxes of at-home Covid-19 test kits after waiting in a long line that snakes multiple times around the Shaw Library in Washington, Wednesday, Dec. 22, 2021. Credit: Andrew Harnik/AP

“We don’t always have 100 percent visibility,” Shah said. “That’s why we build models to estimate how much of the iceberg we are and aren’t seeing.”

Easy access to at-home tests will inevitably mean that state and local officials don’t have a “crystal clear vision” of every new case, he said. However, the greater consideration is making it easier for people to know if they have the virus.

“That’s a tradeoff,” Shah said, “but one that’s well worth making.”

While many experts see the increased availability of at-home tests as potentially revolutionary in stemming the spread, there remain other challenges with the tests, including the cost and often limited availability.

“If you’re already having issues feeding your family or accessing health care, you’re not really going to have $40 or $25 to go get a rapid test,” said Elisabeth Marnik, a science professor at Husson University in Bangor.

Cost is just one of many reasons why people with the virus might never get tested, Marnik said. Other reasons may be lengthy wait times, a lack of symptoms or a lack of desire to get tested for a variety of reasons.

Asymptomatic infections made up 40.5 percent of all people confirmed to have COVID-19, according to a systematic review of nearly 100 studies from across the globe published by the American Medical Association’s JAMA Network Open earlier this month.

The three-quarters of Mainers who have received at least one dose of the COVID-19 vaccine are less likely to show symptoms if they contract the virus. Those who have also received a booster shot are even less likely to show symptoms.

Also at issue is the supply of at-home tests and rapid tests in general.

The current supply is not nearly enough in Maine or the rest of the country, said Dr. James Jarvis, senior physician executive of Northern Light Health’s COVID-19 response.

However, he is optimistic about the federal response to the problem. President Joe Biden announced last week that the federal government would begin supplying half a billion at-home COVID-19 test kits starting in January.

“I’m hopeful that the federal government will be able to meet some of the goals they have put in place to meet that supply so people can get tested sooner,” Jarvis said.

The bottom line, experts say, is to make testing easily accessible, both physically and in price, so more people can isolate themselves before they spread the virus to others. While at-home tests may contribute to an undercount of case numbers, they are a vital part of stemming the spread, they say.

“Anything that we can do to increase that access to testing is an important tool and helps to decrease overall infections,” Marnik said.