What will COVID-19 look like in 2100? Scientists predict three possible scenarios

Imagine it's March 2100. What cars remain are electric, or flying, or both; subways and high-speed rail are the dominant forms of transit. Contemporary architecture is designed around climate change, the main crisis humanity is facing. And as public health leaders around the world gather for an annual summit, they reflect on the 80th anniversary of the COVID-19 pandemic. Just as 2008 marked the 80th anniversary of the 1918 influenza virus pandemic, March 2100 will mark the 80th anniversary of the COVID-19 pandemic. Where will COVID-19 be then?

Of course, nobody can predict with perfect accuracy what COVID-19 will look like eighty years hence. Yet infectious disease experts know a remarkable amount about the SARS-CoV-2 virus two years since its discovery — and they have predictions as to how COVID-19 will play out over the next century.

Those predictions are based on what we've observed about how the SARS-CoV-2 virus has behaved in the past two years. For example, experts know that the virus can mutate to become more contagious, and (to some extent) can evade vaccine-induced immunity; yet we also know that vaccines have proven to be very effective at preventing severe disease and hospitalization, even if they cannot stop breakthrough infections of certain variants. Scientists also know that COVID-19 has a long tail: among those infected with COVID-19, about 10 percent will experience symptoms that can possibly persist as long as two years after an infection.

Knowing these caveats, Salon spoke to experts and scientists about how COVID-19 might look in 10, 20, and 80 years from now. Though their responses had some variation, the main lines of future prediction were remarkably similar.

The best-case scenario

Some theorize that the lesser phase of COVID-19 is already upon us. Indeed, last week, the World Health Organization reported that new coronavirus cases around the world are declining. While deaths by COVID-19 were up slightly, the new numbers did follow a 23% drop in fatalities the week before.

"SARS-CoV-2 will likely be one of the endemic respiratory viruses that humans deal with just like the other four coronaviruses that cause common colds," Adalja said.

Thus, as COVID-19 restrictions are being lifted around the world, many have wondered if the world is finally entering an "endemic phase" — which, in epidemiology, means that the disease is present in a society, but at a baseline level rather than a widespread infection.

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Dr. Amesh Adalja, an infectious disease and critical care medicine doctor, told Salon he believes by 2100 — or "actually much sooner" — SARS-CoV-2 will be endemic.

"SARS-CoV-2 will likely be one of the endemic respiratory viruses that humans deal with just like the other four coronaviruses that cause common colds," Adalja said.

The coronaviruses belong to a class of viruses known as RNA viruses, which also includes influenza, hepatitis C and SARS. RNA viruses like SARS-CoV-2 have relatively malleable genetic codes, prone to mutation; every time they enter a host's cell and replicate, there is a chance that mutations will occur.

As Salon has reported before, this is not always a bad thing, as natural selection tends to favor viruses that are highly transmissible and not those that are necessarily deadliest. Hence, some experts hope is that SARS-CoV-2 has reached peak transmissibility — and, through immunity gained by previous infections and vaccines, the virus will stop mutating or its mutations won't cause more severe disease than we've already seen.

Dr. Monica Gandhi, infectious disease doctor and professor of medicine at the University of California, San Francisco, told Salon she agrees that in the year 2100, COVID-19 will be similar to the common cold. More optimistically, she believes it might not even be as bad.

"The thing to remember about the common cold coronaviruses, rhinovirus and adenovirus and other viruses that cause common colds, is that they can cause severe illness in older people," Gandhi said. "Because even a rhinovirus in a 90-year-old who is otherwise doing well can actually be a cause of death."

"We will have medications that will bring down the viral load of COVID," Gandhi said. "So, actually, I think the outcomes for older people will be better than a common cold."

Gandhi said the difference with COVID-19 is that the world has a vaccine for it. Previously, creating a vaccine for the coronaviruses has been hard to make, partly because of how the virus infects the upper respiratory tract.

"But in this case [of COVID-19], we will have medications that will bring down the viral load of COVID," Gandhi said. "So, actually, I think the outcomes for older people will be better than a common cold."

Adalja said there may soon be a "universal coronavirus vaccine" that "covers SARS-CoV-2 plus other human coronaviruses." He speculated that might arrive by 2025.

Likewise, it is probable that all citizens will be immunized via vaccine by then, as part of a series of childhood vaccinations.

"It's unclear whether vaccination will be at birth or at age 6 months so as not to be blunted because of maternal antibodies," Adalja said, noting that only the hepatitis B vaccine is given at birth.

Medium-case Scenario

Not all infectious disease experts agree that in 80 years, COVID-19 will peter off to the point that it is more benign than a common cold. Among them is William Schaffner, a professor of infectious diseases at the Vanderbilt University Medical Center. When asked if COVID-19 will then be akin to the common cold today, Schaffner told Salon: "I don't think that there's enough information out there for us to be secure in any way."

"There are people who haven't received that first booster yet, and how is it that we haven't been able to communicate, motivate, persuade, comfort and reassure them that this is really the best thing for them in their families to do?" Schaffner lamented, speaking to the difficulties of gaining public trust around the vaccines. "We have major challenges ahead of us in that regard, and if it's necessary for us to do what we do with influenza, more or less to get an annual booster — you can see what a challenge that is."

"It's not as though the virus says 'well, I'd like to get from A to B' and then it designs its genetics to get there — they're random events."

Schaffner added that the way SARS-CoV-2 mutates makes it more difficult to predict the future of COVID-19 because they "occur at random."

"It's not as though the virus says 'well, I'd like to get from A to B' and then it designs its genetics to get there — they're random events," Schaffner said. "And, I suppose, having the virus modulate itself to become more like a regular common cold virus, or developing an entirely new variant that could evade the protection of our vaccine and have the whole Fandango start all over again, they're probably comparable statistically — so I don't know which way this is going to go."

A 2008 study suggested that the virus that causes cold-like symptoms today may have jumped from birds to humans as recently as 200 years ago. But not much is known about this jump, and how severe colds were at the time.

This is one reason why scientists struggle to find a proper historical analogy to draw from in terms of predicting COVID-19's future track. Indeed, on that note, Schaffner added that each group of viruses has very distinctive characteristics. For example, measles is known for its durable immunity — meaning if a person is infected with the virus (or vaccinated against it), they are immune to the virus for the rest of their lives. COVID-19 is different, in that vaccination or infection seems to merely confer transient immunity, meaning short-term immunity.

Moreover, some viruses are difficult to vaccinate against not because of issues with transient immunity, but because of their propensity to mutate. HIV is one: it has been difficult for scientists to develop an HIV vaccine over the last 40 years in part because of how rapidly it mutates.

Nonetheless, Schaffner said by the year 2100 — due to a growing human population and increased travel due to technological advances — humanity can expect to face new epidemics or pandemics as well.

"We are going to encounter a lot of the viruses that are out there in the world that circulate in the animal population, and then have the opportunities to jump species on occasion and get into humans," Schaffner said.

He noted that this situation will be somewhat balanced by an increase in scientific knowledge and advances as well.

"We will continually be making better and better vaccines against more and more of these potential viruses that are out there," he said. "If we don't use them all, we will have the potential to have them on the shelf ... and quickly manufacture vaccines."

Schaffner imagines vaccines will look differently, too.

"We will have vaccines that are delivered by patches on the skin by just taking oral capsules and swallowing them," Schaffner said. "So they will be much easier to deploy rapidly and safely."

Worst-case scenario

Schaffner warned there could be a worst-case scenario that humanity could be looking at 80 years from now.

"That would be the development of a new variant that was very contagious and was more inclined to create more severe disease," he said. "And most importantly, the third characteristic would be that it could distinctively evade the protection of our current vaccines."

Such a nightmare scenario would perpetually extend the pandemic, he warned. "If that happened, that would start basically a new pandemic with another coronavirus, and that would cause once again, an economic, social and political calamity," he fretted.

Schaffner added that in this case, the world would be able to respond more quickly with a vaccines — but noted that the world could face, once again, the issue of deployment.