See more of the story

I hope, in the end, that this article reads as alarmism. I hope that a year from now it's a piece people point to as an overreaction. I hope.

Coronavirus cases are falling. Vaccination numbers are rising. We are already jabbing more than a million people a day, which means President Joe Biden's initial goal of 100 million vaccinations in 100 days was far too conservative. In California, where I live, Gov. Gavin Newsom lifted the statewide stay-at-home order. It feels like dawn is breaking.

And that is what makes this moment dangerous. The B.1.1.7 variant of coronavirus, first seen in Britain, and now spreading throughout Europe, appears to be 30% to 70% more contagious, and it may be more lethal, too. It hit Britain like a truck, sending daily confirmed deaths per million people from about six per million in early December to more than 18 per million today. The situation in Portugal is even more dire. Daily confirmed deaths have shot from about seven deaths per million in early December, to more than 24 per million now. Denmark is doing genomic sequencing of every positive coronavirus case, and it says cases involving the new variant are growing by 70% each week.

"What we need to do right now is to plan for the worst case scenario," Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, told me. "And when I say 'worst case,' I'm potentially talking about the most likely case. Let's not wait until we wrap the car around the tree to start pumping the brakes."

America is doing embarrassingly little genomic testing, but even the paltry surveillance that is being conducted has confirmed epidemiologists' fears: B.1.1.7 is here, too. And there's evidence of another super-contagious strain developing in California. It will take some weeks or even months for these new strains to become dominant, but virologists tell me there is every reason to believe they will. The results could be catastrophic, with hundreds of thousands dying before vaccinations neutralize the threat.

This is the part of the horror film where a happy ending seems in sight, but it is obvious, to those paying attention, that the monster is not dead, and that the worst may be yet to come. We cannot let ourselves be taken by surprise.

Paul Romer, the Nobel laureate economist, told me to think about it this way: The coming months are a race between three variables. There is the contagiousness of the virus itself. There are the measures we take to make it harder for the virus to spread, from lockdowns to masking. And there is the proportion of the country with protection against the virus, either because they've already caught it or because they've been vaccinated. If contagiousness is rising fast (and it is), then the measures we take to stop the spread or the measures we take to immunize the population need to strengthen faster. Romer's modeling suggests that if we continue on our current path, delivering 1 million vaccinations a day and growing fatigued of lockdowns and masks, more than 300,000 could die in the coming months.

But calamity at that scale is a choice, not an inevitability. And so I've been asking health experts the same question: If you knew, with 100% certainty, that the coronavirus would be 50% more contagious six weeks from now, what would you recommend we do differently?

The most immediate danger is that optimism and exhaustion will overwhelm our common sense, and we will reopen just as the new strains are quietly building momentum. "Just in the last week or 10 days," says Ashish Jha, dean of the Brown University School of Public Health, "a lot of state officials are looking at data of numbers coming down and asking me, 'When can I reopen my restaurants to 75%? Bars have been closed for months, can I reopen bars now?' It is true things are coming down but we are at a very high level. This is not the time to start letting up. This is the time to hunker down for what is likely to be a very difficult two or three months."

Let's agree that total lockdown is the most ruinous of all options, and the one we'd like to use least. We have tools we could deploy to avoid it, but we'd need to start quickly. One is rapid, at-home testing. The technology exists to produce tens of millions of cheap, at-home antigen test strips each day. These strips are highly accurate during the period that matters most — when we are infected and contagious. Used widely, they'd let all of us check, daily, if we were potentially infected, so we could then isolate and avoid infecting others. "This is a public health issue and if we don't empower the public to deal with it we won't be able to defeat it," Michael Mina, an epidemiologist at Harvard, told me.

The problem here is the Food and Drug Administration. It has been disastrously slow in approving these tests and has held them to a standard more appropriate to doctor's offices than home testing. "The FDA needs to catch up to the science," Mina said, frustration evident in his voice. "They are inadvertently killing people by not following the science." I asked Vivek Murthy, Biden's nominee for surgeon general, whether the FDA had been too cautious. "I do think we've been too conservative," he told me. Murthy went on to argue that there's a difference between the diagnostic testing doctors do and the surveillance testing the public could do and that the FDA had failed to appreciate the difference. Speeding the FDA on this issue will be an early, and crucial, test for the Biden administration. In this case, Democrats need to deregulate.

Biden has proposed spending $50 billion on testing and a chunk of that money will go to genomic sequencing. This is crucial, because the virus is mutating, and we need to know how, and where, and we need to know it quickly. Natalie Dean, a biostatistician at the University of Florida, told me that this moment feels to her like a year ago, when we knew the coronavirus was spreading, but we didn't have the basic testing to map the problem. "Given that we don't have adequate genomics surveillance, we have the same déjà vu that there is something out there circulating and we're not appropriately measuring it," she said. Congress needs to pass Biden's plan, right now.

Better masking would also make a difference. Many of us — and I include myself here — are wandering around in cotton masks whose construction we know little about. That's better than nothing, but a year into this pandemic, we should have stronger guidance on choosing the most effective masks. "I want to see very direct guidance from the CDC of masks people should be wearing in different contexts," Jha told me. He said that with the new strains, he won't go into a grocery store unless he's double-masked, or wearing an N95, or the South Korean equivalent, a KF94. In September, we learned the Trump administration had scrapped the U.S. Postal Service's plan to send masks to every American residence. During our conversation, I asked Murthy if having the government produce and directly distribute high quality masks is an idea worth revisiting. "I think so," he said.

Then, of course, there's vaccination. We live in an age of marvels. That we already have two vaccines, both of them over 90% effective against the virus, is a wonder. Early testing shows the vaccines easily neutralize the B.1.1.7 variant, and while there is a South Africa strain that shows some resistance to the vaccine, the level of antibodies the vaccine produces should still be sufficient. If it isn't, BioNTech says they could produce a targeted booster in about six weeks.

Biden first promised 100 million shots in the first 100 days of his presidency. Now, he is suggesting that we could reach 150 million. Romer's calculations suggest that 2 million vaccinations a day could keep us ahead of the new strains, and blunt their impact almost entirely. I recognize the political appeal of underpromising and overdelivering, but the danger of a modest goal is that you can fool yourself into believing you've succeeded when in fact you've failed. Biden has said the Trump administration's vaccination rollout was "a dismal failure," and he was right. But if we're delivering 1.3 million shots a day now, even before the Biden administration has implemented their new distribution program, then 2 million per day seems like a reasonable goal to reach for.

There is an end in sight. But this could end with 300,000 more deaths, or it could end with a fraction of that. What we do these next few months will make all the difference.

The new strains spread quickly. The speed of our countermeasures will decide our fate. What feel like reasonable delays in our normal experience of time — a few weeks here for Congress to debate a bill, a few weeks there for the FDA to hold meetings — could lead to the kind of explosive infections that overwhelm our hospitals and fill our morgues.

Ezra Klein joined New York Times Opinion in 2021. Previously, he was the founder, editor in chief and then editor-at-large of Vox; the host of the podcast "The Ezra Klein Show"; and the author of "Why We're Polarized." Before that, he was a columnist and editor at the Washington Post, where he founded and led Wonkblog.