To help make sense of where we’re at in battling the coronavirus pandemic, infectious-disease expert Michael Osterholm, PhD, MPH, strives to keep things simple: He compares the situation to a baseball game.
“We’re just in the second inning of a nine-inning game.” And our tactics now, he says, will determine how that game plays out.
Having served for 15 years as Minnesota’s state epidemiologist, Osterholm is director of the University of Minnesota’s Center for Infectious Disease Research and Policy (CIDRAP). He’s authored more than 315 papers on infectious diseases, and he coauthored the 2017 book Deadliest Enemy: Our War Against Killer Germs. He’s been called “the Paul Revere of pandemics” and, far less flatteringly, “Bad News Mike.”
For more than two decades now, Osterholm has been warning the world about the possibility of a global pandemic at least as infectious as the 1918 flu outbreak that killed some 50 million people.
It’s a warning that he feels largely went unheard and unheeded.
“People just didn’t have a sense of the immensity of this before. If someone had described six months ago where we’re at today — the deaths, the economy, the food-supply problems, you’d say, ‘What?’” Osterholm says. “Here’s a disease that just 90 days ago wasn’t even among the top 100 causes of death in North America and much of last month was the No. 1 cause of death.”
Back in March 2020, when the pandemic was largely breaking news to most of us, he wrote in a New York Times opinion piece that it was already “too late to avoid disaster.” Since then, his CIDRAP team has continued to try to steer us to “develop a strategy to prevent the worst.”
How Does COVID-19 Compare to Past Pandemics?
To look ahead, Osterholm first looks backward. He compares the current pandemic to past influenza epidemics to gauge what could happen and how to plan for it.
The first concern is that the coronavirus is far more infectious than the flu. He explains three reasons for this:
- Longer Incubation Period: COVID-19 takes more time to incubate — five days on average (or a range of two to 14 days), versus an average of one to two days for the flu. This makes the coronavirus able “to move silently in different populations before being detected.”
- More Asymptomatic Spread: During that incubation period before symptoms surface, the coronavirus spreads more easily, and 25 percent or more of all cases may be asymptomatic — almost double that of the flu.
- Higher Reproductive Rate: The reproduction number (R0, pronounced “R-naught”) is the average number of new infections that result from a single infected person; the coronavirus’s R0 is believed to be 2 to 2.5 — again, double that of most common influenzas, although some severe pandemic influenzas have also been as high as 2.
But the coronavirus’s R0 can explode exponentially in places of high population density or more frequent contact, such as we’ve seen in New York City. Plus, certain people with COVID-19 can be far more infectious than others for unknown reasons; they’ve become known as “super spreaders.”
Based on these factors, Osterholm’s team published a white paper on April 30, 2020, outlining what we can expect from the pandemic. In sum, Osterholm sees the rest of the ball game playing out “for at least another 18 to 24 months of significant COVID-19 activity without a vaccine.”
Working Toward Herd Immunity
“COVID-19 will go away eventually in one of two ways,” Osterholm explained in a Washington Post editorial on March 21, 2020. “Either we will develop a vaccine to prevent it, or the virus will burn itself out as the spread of infection comes to confer a form of herd immunity on the population. Neither of those possibilities will occur quickly.”
This concept of herd immunity implies that immune protection is lasting and is key to eradicating the virus. A single person may build immunity to the coronavirus by naturally building antibodies or, more commonly, by having them bolstered by vaccines.
But to control the spread of the disease throughout the population, a larger portion of us — the so-called herd — must develop immunity. This way, the virus can’t continue to spread because there are fewer and fewer victims for it to infect. (For more on herd immunity, see “What Is Herd Immunity, Anyway?”)
“We won’t see transmission stop or slow down until we get to 60 or 70 percent of the population infected,” says Osterholm. “It doesn’t mean when you hit 60 or 70 percent it stops — it just slows down.
“If the pandemic follows the traditional influenza pandemic model, then we can expect probably a lot of outbreaks in late summer and early fall — major outbreaks, much more than we’ve had to date. The peak you saw in New York could be just a small blip on what could happen.
“Remember, we have a long ways to go from just 5 or 15 percent of the country infected, which is where we’re at today, to 60 or 70 percent. That’s not something people want to hear, but that’s exactly where we’re at.”
And he doesn’t know for sure how we’re going to reach herd immunity.
“Our goal obviously is to try to get to a vaccine, which is very, very important. If we can do that, then that’ll help us get to that immunity status without having to have people end up dying from it or getting sick.”
Still, Osterholm expects it will be some 18 months — well into 2021 — before a vaccine is ready for much of the world.
How Have Other Countries Fared With COVID-19?
In addition, looking at how other countries are coping is inconclusive. Every country is facing a unique situation, dependent on geography, political, and healthcare systems — and other concerns. So assessing which countries are doing things right is all relative, Osterholm explains.
Several countries went into immediate lockdowns, and while this had great benefits early on, their evolving situations are either problematic or tenuous, he says.
“Everyone thought Singapore was doing it just right — and then suddenly they’re in a national state of emergency when the foreign migrant population really became a major challenge.
“New Zealand right now has basically declared that they’ve eliminated it. They’re an island country, and that status is as good as one air flight coming back with a case.”
Sweden followed the opposite strategy of working toward herd immunity by largely letting the virus loose. “Sweden has paid a hell of a price,” he states, considering the coronavirus has killed a high percentage of the country’s elderly in long-term-care facilities. “When you look at the Swedish numbers, it may seem at first that they were doing things just right, but then when you realize the number of deaths they’ve had has far, far, far outstripped Denmark, Norway, Finland, and Iceland. Two months ago they were neck and neck with them, you might say, and now suddenly they’ve really taken off. That is not a model many of us would agree with.”
And even countries like China that imposed a lockdown and thought they had conquered COVID-19 saw cases appear months later.
“Everyone thought that with their lockdown they had developed the means with which to stop this. Well, they may have been able to slow it down, but again this virus is so infectious that the challenge we have is that it’ll come back. And unless you have a completely virus-proof bucket, it’s going to leak out.”
Scenarios for the Future
In his team’s white paper, Osterholm outlines three scenarios they foresee for the pandemic’s future.
Peaks and Valleys: The first peak of the pandemic (which was in spring 2020) is followed by a slight valley (which we’re in now, at the start of the summer); these peaks and valleys will continue through the summer and over a one- to two-year period, fading away sometime in 2021. The peaks and valleys will likely vary geographically.
Fall Peak: The spring 2020 wave is followed by a much larger peak in fall or winter 2020 and smaller, subsequent waves in 2021. This pattern occurred during the 1918 flu epidemic, and will require foresight, planning, and care so that hospitals are not overwhelmed.
And fighting off the coronavirus in the fall doesn’t mean we’re safe from an autumn flu-season pandemic on top of it, Osterholm warns. “This does not preclude an influenza pandemic in any way, shape, or form. Unfortunately, this pandemic was really an add-on event. It doesn’t replace an influenza pandemic.”
Slow Burn: The spring 2020 wave is followed by an ongoing, lower-level series of virus transmissions and cases until COVID-19 is eradicated. No major influenza pandemics in the past have followed such a pattern, but Osterholm says it is a possibility, however remote.
No matter which scenario takes place, he says, COVID-19 is not going away completely. “[It] will continue to circulate in the human population and will synchronize to a seasonal pattern with diminished severity over time.” This has been the pattern of some influenza viruses as well.
“People ask me, ‘What drives this virus? Why does it do this?’” Osterholm says. “It’s basically ‘viral gravity.’ It’s just like physical gravity: You drop something and you know which way it’s going to go. This virus is going to keep working to find people to infect until it runs out.”
The advantage of years studying infectious diseases is that Osterholm has thought of all the worst-case scenarios — hopefully. So far, he says, there’s nothing about the pandemic that has surprised him, including the side effects and collateral damage of unemployment, a turbulent stock market, and food concerns. He didn’t earn the nickname Bad News Mike for nothing.
Our task now is to thread a rope through a needle, Osterholm explains.
“We can’t wait until we have herd immunity. We can’t go into complete lockdown; we’d destroy society as we know it,” he says, listing dire possibilities including a depression, or even complete economic breakdown. “And we can’t just let cases go willy-nilly or we’ll burn down our healthcare system, and that way not only will the number of deaths from COVID-19 go up substantially, but deaths across the board from any number of causes will go up.
“So, the challenge is how we release people into the public domain so that they can continue to work, they can continue to socialize — knowing that many of them will get infected.”
Organized coronavirus and antibody testing is crucial, but we’re still a long way from accurate tests, as he outlined in another New York Times editorial critiquing the FDA’s oversight: “There aren’t enough. Many are shoddy. Most aren’t even designed to tell us what we really want to know. . . . As a result, coronavirus testing in the United States is a Wild West.”
First, the tests themselves need to be refined and perfected. “A very precise test is able to correctly identify both the presence of any antibodies if they are present (this is known as ‘sensitivity’) and the absence of antibodies when they are not there (this is ‘specificity’),” explains Osterholm. “But sensitivity and specificity are somewhat at odds with each other, and they compete. For instance, the characteristics that make a test more sensitive, or better at turning out true positives, also make it more likely to yield false positives instead of what should be true negatives.”
Second, more people need to get infected to, simply put, make the math work: With a low prevalence of the population actually having COVID-19 antibodies, even the best test will show more false results.
“It is also a principle of epidemiology that the lower the prevalence of an infection in a studied population, the greater the chance that testing for antibodies will yield false positive results,” he states. “That’s because when testing in a population with few total cases of infection, the number of false positives will make up a larger share of all positive results.”
This also means the concept of immunity passports is still far in the future. Such documents or some other sort of immunity bracelet or ID may perhaps someday be issued to document who has been tested and found positive for antibodies. Osterholm blames much of the testing woes on the lack of federal leadership in not overseeing the plethora of tests.
“Of all the resources lacking in the COVID-19 pandemic, the one most desperately needed in the United States is a unified national strategy, as well as the confident, coherent, and consistent leadership to see it carried out,” Osterholm states. “The country cannot go from one mixed-message news briefing to the next, and from tweet to tweet, to define policy priorities. It needs a science-based plan that looks to the future rather than merely reacting to the latest turn in the crisis.”