If you have been looking for a sense of pandemic closure, the World Health Organization’s declaration Friday that it was ending the Covid global health emergency was about as close to it as you are likely to get.
The reality is that although battlefield metaphors are often employed to describe humankind’s struggle with the SARS-CoV-2 virus, there will be no 11th hour of the 11th day of the 11th month-like moment signaling that an armistice has been achieved.
There are no fixed borders between a pandemic, when a pathogen is new to humans and causing wide scale disease and often high levels of death, and the ensuing endemic phase, when the disease has settled into something that our immune systems can better cope with, explained Marc Lipsitch, an infectious diseases epidemiologist at the Harvard School of Public Health.
“It’s not like ‘What is an electron?’” he told STAT in an interview. “These are not questions that have right and wrong answers. I mean, they have some wrong answers, but they don’t have any unique right answers.”
What is clear is that Covid isn’t going anywhere, though the damage it is doing to the human species is declining. We are getting on with life. “The death toll is going down and the ability of society to function is going up,” Lipsitch said.
Because Covid transmission isn’t going to cease, there is no actual end to point to. Instead, epidemiologists and medical historians look for signs that the virus is transitioning into something that is more predictable and less dangerous. That’s a journey whose timing is influenced by both how the virus evolves and how quickly our immune systems acquire the capacity to cope with the new disease.
When WHO Director-General Tedros Adhanom Ghebreyesus announced the end of the Public Health Emergency of International Concern, there was a valedictory tone to the remarks he and other senior WHO officials made. Tedros thanked the WHO’s staff for their efforts; Maria Van Kerkhove, the WHO technical lead on coronaviruses, was visibly emotional at a point when she talked about the people who died without family by their bedsides, the funeral pyres some countries used to deal with Covid corpses.
Still, Tedros described the milestone as the end of the emergency phase of Covid, though not the end of the threat Covid poses to people. Last week, Covid claimed a life every three minutes, he said, “ and that’s just the deaths we know about.”
Lipsitch said he thought the director-general’s framing was the right way to think about where we are now with Covid-19. Deaths — hovering around 1,000 a week at this point in the United States — are still too high, he said “but lots of things are much worse than they should be and we don’t treat them as emergencies.” In the U.S., the Covid public health emergency will expire this Thursday, May 11.
Cecile Viboud, an infectious diseases epidemiologist at the National Institutes of Health’s Fogarty International Center, has studied in great detail the 1918 flu pandemic, the worst on record, as well as the three flu pandemics that followed it, in 1957, 1968, and 2009.
Based on her work, Viboud would expect to see the virus behave differently in the post-pandemic phase than it did during the acute crisis. For instance, she would expect more predictability of when Covid activity would peak and wane — in other words, a discernible seasonality. The impact of those epidemics would be largely similar, with some fluctuation, sure, but not the high, high spikes of activity seen in the pandemic. Likewise, the age distribution of cases — or at least the most severe cases — would settle into a pattern.
“I’m not sure we’re quite there,” Viboud said. “I think we’re in that slow transition phase.”
She acknowledged, though, that this pattern she’s watching for is one based on the tail ends of influenza pandemics. “That’s all we have,” she said. The way a coronavirus pandemic ends might look different, she admitted. “These three years have taught us that you have to remain humble and realize that there might be something that you haven’t thought about, and it could be completely different than you believed.”
That is another problem with trying to figure out when to think about the pandemic as being well and truly over. We have never experienced a coronavirus pandemic in the age of virology, so there is no history to scour for patterns.
Four other coronaviruses, which are among the viruses that cause what we call the common cold, jumped from some animal source to humans at some point in the past. But there are no reliable records of any of those events, so if there are signposts we should be looking for, they are unknown to us.
(There is some thought that a pandemic in 1889, known in the history books as the Russian flu, might actually have been the emergence of one of those human coronaviruses, OC43. But it is — and may remain — only a theory.)
The experts STAT spoke to for this article were not comfortable with saying that the Covid pandemic is over. But they shared the WHO’s opinion that it is in a different phase.
“I agree that we may be on the backside of this pandemic. And I think that every piece of data that we’ve seen in the last four months would support that,” said Michael Osterholm, director of the Center for Infectious Diseases Research and Policy at the University of Minnesota.
But a looming question remains about what will happen with the evolution of the virus. Will a major new variant of concern, a version of the virus that is as different from Omicron as Omicron was from Delta, emerge and cause a large new wave of infections? Experts hope not, but say there’s no way to know for sure. The WHO indicated it might need to declare another public health emergency, were that to happen.
“At this point, we won’t know for some time if in fact this is going to continue to wane, and [we’re] going to continue to see a reduced number of severe illnesses, hospitalizations, and deaths. Everything right now says it will. But I reserve that judgment. You can’t say it’s over,” Osterholm said.
Viboud agreed that we’ll have a better sense years down the road of how to define the period of the Covid-19 pandemic. “Ten years from now we’ll be able to say, oh yeah, this is when things went back to normal.”
She’s not as concerned, though, about the emergence of a new variant, suggesting we’ll be better equipped to deal with it.
“By that point, the entire population will have seen Covid — many, many different types of Covid — many times, and [some will have been] vaccinated many times,” she said. “I think a new variant, even if it was Omicron-like, would not have the same impact Omicron had, just because the immune landscape is different.”
In some respects, the end of a pandemic isn’t just about the behavior of a virus, or of our ability to cope with the infection it causes. The willingness of people to make concessions to the virus is also a contributing factor.
Historian John Barry, who wrote a bestselling book about the 1918 pandemic, “The Great Influenza,” noted that in some places in the United States, the flu activity in 1920 was as deadly as what was seen in three waves in 1918 and 1919. But historians don’t consider that activity as part of the Spanish flu pandemic — because public health authorities at the time didn’t characterize that activity as a fourth wave, and they did not impose any measures to try to limit spread.
“Nobody did anything. You had one-third more deaths, in a shorter time frame, in 1920 in Detroit than you had during the fall outbreak of 1918. And yet nothing was done,” Barry said.
He has been observing a similar desire to move on from Covid, noting that while he’s still invited to give talks about the pandemic, the audiences he speaks to are getting smaller and smaller.
In December, he was a featured speaker at a conference of hematologists, an event that brought 30,000 physicians and researchers to New Orleans, where Barry lives. The session was booked for a huge hall. He estimates about 200 people attended the talk.
“These are people who are scientists. And obviously one of the main issues with Covid is its impact on various blood disorders and clotting and so on,” Barry said.
“Even the medical community doesn’t want to hear about it.”