With COVID-19, it’s sometimes been hard to see what’s coming next. But you could do a lot worse than following Jeff’s story.

Jeff, a 62-year-old Massachusetts resident with a vacation home in the Somerset County town of Embden, was among the first out-of-staters to come to Maine to wait out the pandemic — way back in March 2020. Such virus-related escapism is now commonplace.

Jeff was also among the first people within Maine’s borders to test positive for COVID-19, and one of the first to go through the boredom, isolation and trepidation of quarantine.

Now Jeff, who for the past year has been telling his story to Scott Monroe of the Kennebec Journal/Morning Sentinel, is among the first group of survivors to experience COVID-related problems well after they supposedly recover.

From “long-haulers” like Jeff, doctors and researchers are trying to learn what they can about the long-term effects of COVID-19. What they know so far is troubling and must be a major focus going forward.

For good reason, everyone’s attention for the past year with respect to COVID-19 has been on deaths and hospitalizations.

People like Jeff won’t turn up in those statistics, as his case was relatively mild, mostly causing trouble breathing.

The real problems, however, started after Jeff tested negative and moved back to Massachusetts. He began experiencing sudden spikes in his heart rate to go with shortness of breath, as well as an irregular heartbeat that required medication.

While lung injuries and other respiratory problems are more often associated with COVID, heart damage can occur as well. According to the American Heart Association, nearly a quarter of people hospitalized with COVID have cardiovascular complications.

Researchers are finding, too, that the long-term effects can linger even for people, like Jeff, who only experienced minor symptoms. One of the first studies covering such people found that they suffered long after their initial diagnosis, not only from heart problems, but also anxiety, fatigue, insomnia and gastrointestinal problems, to name a few.

More than 60 days after infection, the study found, 27% were struggling with at least one of the symptoms, hampering their ability to work and function normally. The symptoms were present across all age groups. Nearly a third of those experiencing symptoms felt fine during the time immediately after infection.

The National Institute of Health, among others, is now studying COVID “long-haulers” to discover its causes and formulate prevention and treatment strategies.

It’s important to find out how these various symptoms are related and perhaps who is at the highest risk for long-term COVID. The U.S. has recorded more than 29 million cases of COVID, and counting, with more than 19 million coming just since November.

It’s true that most of those cases will be mild.

But that doesn’t mean we can just forget them. In the next year, millions of Americans will be held back by long-term COVID, through a mechanism that is not well understood.

That’s what’s next. We should be ready for it.