In April, Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, and his colleagues presented some potential scenarios for the coronavirus pandemic. One of their models showed a spring wave followed by a trough and then a massive peak in the fall or winter, caused by a devastating resurgence of infections — similar to the trajectory of the 1918 influenza pandemic.

But Osterholm isn’t thinking about a second major wave anymore.

That's because he doesn’t believe the virus will let up, he said. Instead, he suspects it will continue in one ongoing onslaught.

“I think this thing is just gonna continue to burn, hot, hot, hot like a forest fire. As long as there is human wood to burn, it’s going to find it, it’s going to burn it,” he said.

But are we prepared to keep fighting a “forest fire”? While Osterholm recognizes that health care workers have gotten better at treating COVID-19 patients, the strain on nurses and doctors has been considerable, he said. He fears their “heroic work” will not be sustainable and that there could soon be a shortage of skilled medical personnel to confront the ongoing crisis. Indeed, a recent report by Amnesty International found that more than 3,000 health care workers around the world have died from the disease.

In May, Osterholm called the rush to reopen a “hodgepodge” because several states had ignored health and safety guidelines. Now, as the pandemic rages on, he is convinced that much of the country loosened lockdown measures far too early, and now we are paying the price.

The only way to get control of the virus will be to reimpose lockdowns in some states, then reemerge very slowly, “in a measured way” and try “very hard just to keep those case numbers at a low level without significant damage to the economy or society” until a successful vaccine is developed, Osterholm said.

He gives credit to other countries and even some states, such as New York, that have demonstrated that stringent mitigation strategies can reduce infection rates. But for Osterholm, the question remains: Are we willing to follow in their footsteps? Can we drive cases down with what he describes as “smart testing” and contact tracing, with the understanding that even after all of that we still won’t be able to let our guard down?

“I’m not sure what humans will do,” Osterholm said. “I’m more sure what the virus will do.”

He pointed to the problems Germany faced with a resurgence of the virus, which began at a meat-processing plant — despite the fact that the country had been applauded for its initial handling of COVID-19 — as evidence that constant vigilance is still needed, he said.

Osterholm is one of the country’s leading infectious disease epidemiologists, and years ago he warned that “time [was] running out to prepare for the next pandemic.” But he still remains humble about — and humbled by — the new coronavirus.

He is quick to acknowledge that “we don’t really understand coronavirus immunology yet” — he and his colleagues are still trying to figure out how the body protects itself against infection and how long antibodies might protect someone from reinfection.

He also worries about the further pain the pandemic will inflict on the country and predicts we could easily see a death toll of between 850,000 and 950,000 deaths or more without a vaccine. But he is uncomfortable speaking about death in an abstract, statistical way.

“These are real people … loved ones, these are people’s companions — their daughters and sons and mothers and fathers,” he said.

The virus may be a professional concern for Osterholm, but it also remains personal. One of the “best days of his life” came a few weeks ago, on Father’s Day, when he finally saw his five grandchildren, whom he hadn’t seen in months. Osterholm cried and hugged each of them, but it was “for less than a minute in a close-contact setting,” he said, since he is in his late 60s and thus would be at high risk if he got sick from COVID-19.

Osterholm described the brief meeting as a “safe move,” and it was one he clearly needed in this age of what he prefers to call physical distancing.

His advice for others?

“More now than ever, never social distance,” he said.

Follow Elizabeth Ross on Twitter: @eross6.