Will the public trust a vaccine that arrived so quickly?

In early September, officials in South Korea announced an ambitious plan to vaccinate 30 million people against the flu — 10 million more than last year, an increase aimed at keeping down rates of the flu while the country battled the coronavirus.

But as the New York Times recently reported, the internet soon got in the way. As the vaccine was distributed, a few logistical problems popped up, and South Koreans began circulating grave stories online — pictures of vaccine boxes that looked like they had been stored unsafely, reports of vaccine contaminated with mysterious white particles.

Then things got more serious. A 17-year-old died after getting the vaccine. Stories of more deaths began to pour in. "By Oct. 22, the reported death count had reached 28 and it was rising by the day," the Times reported. "Singapore briefly suspended the use of a South Korean vaccine after the deaths were reported."

Health officials were confident that the vaccine was safe, and they eventually determined that the deaths were coincidental. People die every day from a wide variety of causes, so it's not surprising that among millions of people receiving vaccinations, some would die soon afterward for unrelated reasons. But online, the fear would not bend to rational explanation.

As the government took the time to thoroughly investigate the cases, "anxiety grew, trust fell and the vaccination program suffered," Dr. Ki Mo-ran, an epidemiologist, told the Times.

This, I worry, is a taste of things to come in the United States.

In the last few weeks we've been blessed by spectacular news. "Operation Warp Speed," the Trump administration's program to expedite coronavirus vaccines, has been an amazing feat of science and public policy. Clinical trials suggest that vaccines made by Pfizer and Moderna are each safe and effective at preventing infections of the coronavirus; a third company, AstraZeneca, has also reported positive results with its vaccine, though scientists are less confident about its findings.

Yet we might still snatch defeat from the jaws of victory. A vaccine is most effective if a large portion of Americans take it — and on that question, recent history leaves me with a sour feeling.

Americans in 2020 exist in splintered realities. A large number of us believe one truth about Ukraine, face masks, hydroxychloroquine, climate change and the results of the presidential election; almost as large a number of us believe the opposite.

How can we prevent the coronavirus vaccines from falling into that perilous reality gap? The next few months could be pivotal, vaccine experts told me. With a new president in the White House, a loose-cannon ex-president who retains a hold on public attention and an internet-driven media ecosystem adept at minting rumor and outrage, there will be ample room for missteps.

What worries me most is that Americans' decisions about whether to get vaccinated against the coronavirus might become less about science than about identity.

Getting people to trust vaccines is a long-studied question in public health. Jonas Salk's vaccine for polio, one of the most devastating communicable diseases of the 20th century, was popular after it was tested and declared safe in 1955; rates of polio quickly fell.

Other vaccines gained traction slowly. Though vaccinations against measles, whooping cough, diphtheria and rubella were first offered much earlier, it took until the 1990s for vaccination rates to eclipse 90%.

More recently, the internet has accelerated a global movement against vaccines — the so-called anti-vaxxers. Their numbers are relatively small, and the United States still has high rates of immunization. But because vaccine skeptics tend to be savvy about marshaling social media, they've wielded outsize influence in debates over vaccines, leading to a resurgence of measles and other preventable diseases in some communities. Now they could cause trouble in the rollout of coronavirus vaccines, too.

"The anti-vaxxers were very involved in the reopen movement, and in the anti-mask movement, and in the reject-all-scientific-evidence" movement, said Renée DiResta, the technical research manager at the Stanford Internet Observatory and a longtime scholar of how these groups use the internet.

While DiResta expects that Americans are sick of isolation and will be eager to get vaccinated, she fears that in some geographic or social circles, anti-vaccine activists will wreak havoc.

"In certain communities, the low rates could mean that the vaccine is not as effective as it could be, and so diseases continue to take hold," she said.

In September, a poll by the Kaiser Family Foundation found that two-thirds of Americans worried that President Donald Trump was rushing the vaccines for political reasons.

Brewer also fears a slide into partisan warfare. "We don't have much history with vaccination being a right or left issue — vaccination is pretty well embraced across the political spectrum," he said. But on the right, there is a strong resistance to government mandates, which might play into increased skepticism about getting vaccinated.

South Korea's public health officials have been praised for the transparent way they investigated and shut down misinformation about the flu vaccine, but rates of vaccination remain low — only 19 million people have gotten the flu shot, far short of the goal of 30 million. Still, Bruce Gellin, the president of global immunization at the Sabin Vaccine Institute, told me that Americans should allow scientists, rather than politicians, to take the lead in communicating about vaccines, as the Koreans did.

"If you do the math, you can anticipate that strokes and heart attacks will occur within days and weeks of being vaccinated, and since these are common occurrences, every media market will have a story about this — the person was fine, and then following vaccination they had a stroke," Gellin told me. "That speaks to the need to keep our eyes open for things like this — to anticipate them and to look into them."

Preparing for these incidents requires setting up monitoring systems early and investigating problems quickly and transparently in a way that solidifies public trust — in other words, exactly the sort of competence that has been missing from the Trump administration's coronavirus plans.