Mutated versions of the coronavirus threaten to prolong the pandemic, perhaps for years — killing more people and deepening the global economic crisis in the process.

The big picture: The U.S. and the world are in a race to control the virus before these variants can gain a bigger foothold. But many experts say they already expect things to get worse before they get better. And that also means an end to the pandemic may be getting further away.

• “It may take four to five years before we finally see the end of the pandemic and the start of a post-COVID normal,” Singapore’s education minister said last week, according to the Wall Street Journal.

Where it stands: "There are essentially two separate COVID-19 epidemics," Dutch officials said recently, referring to the original strain of COVID-19 and the burgeoning threat from mutated versions of the virus.

• There’s light at the end of the tunnel for the first epidemic. Although the virus is still spreading uncontrolled across the U.S. and much of the world, cases and hospitalizations are down from their peak, and vaccinations are steadily increasing.
• But the next iteration, fueled by variants of the virus, is already taking hold.

What’s next: A British variant of the coronavirus will likely become the dominant strain within the U.S. pretty soon, experts say. It’s significantly more contagious than the virus we’ve been dealing with so far, and some researchers believe it may also be about 30% more deadly.

• “That hurricane's coming,” Michael Osterholm, an infectious disease expert at the University of Minnesota and Biden transition adviser, said Sunday on “Meet the Press.”
• A more contagious and more lethal strain of the virus could easily send cases, hospitalizations and deaths soaring right back to record levels, even as vaccinations continue to ramp up.

“We are going to see something like we have not seen yet in this country,” Osterholm said.

• It’s already happening in the U.K., where skyrocketing hospitalizations prompted another round of lockdown measures — and pushback against those restrictions.

Vaccines work against the British variant, and they will help control its spread, just as they’ll help control the pandemic overall.

• But vaccinations can only ramp up so quickly. The Biden administration is trying to push doses out the door as fast as it can, but there’s a very good chance the more contagious virus is moving faster.
• The existing vaccines don’t appear to work as well against some other variants, including a particularly troubling one first identified in South Africa. They do work, and they appear to prevent serious illness and death, which are the most important things — but they may not prevent as many infections overall.
• Vaccine makers can rework their recipes and come up with booster shots to help address more resistant strains, but that will take time.

How it works: All of these problems stem from the same underlying problem — the unchecked spread of the virus.

• More cases mean more hospitalizations and more death. Bigger outbreaks also provide more opportunities for mutations to arise, and to spread.
• A more transmissible virus means that a greater share of the population — maybe as much as 85% — would have to get vaccinated in order to reach herd immunity. That’ll be a stretch, given the widespread vaccine hesitancy across the country.

Because vaccine production is still scaling up, getting things under control well enough to head off a second phase of the pandemic would have to rely heavily on social distancing and mask-wearing.

• That’s not a very promising position to be in, especially for a country like the U.S.

The bottom line: Vaccines work, and they are still the key to ending this pandemic. But leaning on them almost exclusively only makes the job harder and will likely prolong this pandemic for years.