How the pandemic could end

It’s still the early days of the coronavirus pandemic, but history, biology and the knowledge gained from our first nine months with COVID-19 point to how the pandemic might end, Eileen and I write.

The big picture: Pandemics don’t last forever. But when they end, it usually isn’t because a virus disappears or is eliminated. Instead, they can settle into a population, becoming a constant background presence that occasionally flares up in local outbreaks.

What’s happening: The pandemic is deepening in the U.S., Europe and elsewhere in the world.

• Experts — from the K.’s chief scientific adviserto pharmaceutical CEOs to the WHO — increasingly say SARS-CoV-2 is likely to circulate in the population on a permanent basis, mainly due to the foothold the virus has already established.
• But what damage endemic COVID-19 causes will depend on different factors, including how often people are reinfected, vaccine effectiveness and adoption, and if the virus mutates in any significant way.

“If the vaccine is really effective, like the measles vaccine or the yellow fever vaccine, it’s just going to land like a ton of bricks and suffocate this. Maybe not quite eradicate it — yellow fever and measles are not eradicated — but it’ll be an utter game changer,” UC Irvine epidemiologist Andrew Noymer says.

• But if the vaccines are less effective — as many experts expect for at least the first generation — COVID-19 may eventually behave more like the seasonal flu, Noymer says. (Still, the death rate of COVID-19 currently well eclipses that of the seasonal flu.)

Reinfection is “the big issue,” says Columbia University’s Jeffrey Shaman, who recently described how reinfection and other factors would affect the spread of SARS-CoV-2 if it became endemic.

• So far, there are just a handful of documented reinfection cases, but evidence about whether people retain their antibodies after infection is mixed, and a lot of unknowns remain about the likelihood of reinfection.
• The worst-case scenario would be that there isn’t a vaccine or long-lasting immunity and people get COVID-19 repeatedly and are just as likely to end up in the hospital as with initial infections, Shaman says.

“I would say COVID-19 is already endemic,” says Larry Brilliant, an epidemiologist who worked to eradicate smallpox and now chairs the nonprofit Ending Pandemics.

• With about 59,000 new cases per dayin the U.S. alone, Brilliant says “it is already everywhere.”
• “The real question is: How does it all end?”

Eventually, COVID-19 could end up in “the retirement village of coronaviruses,” like HIV, which today can be treated to the point of elimination or circulate at low levels and be kept in check with a vaccine, like measles, Brilliant says, laying out a handful of possible scenarios.

• But Noymer speculates after its “cataclysmic emergence,” COVID-19 may eventually fade into a common cold after a decade or so.

What’s next: “We have to work with it as a virus that we will be contending with for years possibly,” Shaman says.

• Until we have an effective vaccine and better contact tracing and testing, Johns Hopkins University epidemiologist Justin Lessler says public health measures should continue encouraging the use of face masks and social distancing.

The good news: Viruses can sometimes become milder with time, treatments are already becoming more effective and vaccines can be improved.

• “Right now we are frightened, depressed and on our back heels. We will be able to conquer this disease,” Brilliant says. “It will be a matter of time and science.”

Πηγή: axios.com