The possibility that the American population might be able to achieve some kind of herd immunity to the novel coronavirus without a vaccine seems to be slipping away.
Or at least that’s the worrying implication of a new study that appeared Friday in The Lancet, a medical journal. Experts said the research clarifies the desperate need for a vaccine, and the risk of letting up on social distancing and other safety measures in the meantime.
Welcome to Rabbit Hole, where we dive deep on the biggest story. It’s for Beast Inside members only. Join up today.
ADVERTISEMENT
This summer, Stanford University researchers Shuchi Anand, Maria Montez-Rath, Jialin Han, Julie Bozeman, Russell Kerschmann, Paul Beyer, Julie Parsonnet, and Glenn Chertow analyzed blood plasma from 28,503 dialysis patients across the United States. They searched for signs of the novel coronavirus from the initial surge of infections during the spring.
Dialysis routinely leaves behind “remainder plasma” from patients’ blood. That plasma is a convenient way of quickly studying “seroprevalence”—that is, evidence of an immune response—in a large swathe of the population. As a bonus, scientists can look up each dialysis patient’s age, sex, race and hometown, helping them to understand how the virus disproportionately harms certain communities.
In analyzing the plasma, the Stanford scientists looked for the kinds of antibodies the human immune system typically produces when confronted with the SARS-CoV-2 (or novel coronavirus) pathogen. “Measuring the seroprevalence of … antibodies provides a comprehensive assessment of its community spread,” the team wrote.
The scientists found these antibodies in 9.2 percent of the sample population, overall. It’s that small proportion that startled Otto Yang, an expert in infectious diseases at UCLA.
“All the death and destruction that we saw so far—all of that is associated with still a pretty low percentage of the population being infected,” Yang told The Daily Beast.
As expected, the infection rate wasn’t uniform. “Not everyone is at the same risk,” Jeffrey Klausner, a professor of medicine and public health at UCLA who previously worked at the U.S. Centers for Disease Control and Prevention, told The Daily Beast.
“Residents of non-Hispanic Black and Hispanic neighborhoods experienced higher odds of seropositivity … compared with residents of predominantly non-Hispanic white neighborhoods,” the researchers found, echoing studies and reports showing the same thing. “Residents of neighborhoods in the highest population density quintile experienced increased odds of seropositivity … compared with residents of the lowest density quintile.”
Those findings are consistent with other research highlighting the special risk that people of color and city residents face compared to white and rural populations.
Yang extrapolated the Stanford team’s findings. If the natural infection of just 10 percent of the population can overwhelm the health systems in major cities and lead to hundreds of thousands of deaths and countless long-term illnesses—not to mention social and economic hardship—imagine what would happen if authorities gave up on containing the novel coronavirus. The idea is that 340 million Americans would run the risk of unmitigated exposure, and a majority would develop some level of protection by way of infection, illness, and—in some cases—recovery.
“Herd immunity would require 60 to 70 percent of the population,” Yang pointed out. “Here we are at less than 10 percent. The simple conclusion is that there’s no way the system can handle the strain it would take to reach that.”
Still, some politicians, including President Donald Trump and U.S. Senator Rand Paul, a Kentucky Republican, continue to advocate for a herd-immunity strategy—or at least flirt with one.
During a Senate hearing on Wednesday, Paul clashed with Anthony Fauci, the longtime director of the National Institute of Allergy and Infectious Diseases, on this very subject. Paul claimed that New York’s low rate of active COVID-19 cases could be due to the state’s population developing herd immunity—and not social-distancing measures.
Fauci shot back, pointing out that just 22 percent of New Yorkers have been infected—just a third ofwhat the state could require for herd immunity. “If you believe 22 percent is herd immunity, I believe you're alone in that,” Fauci said.
Elitza Theel, the director of the Infectious Diseases Serology Laboratory at the Mayo Clinic in Minnesota, sided with Fauci. It takes an overall seroprevalence of 60 percent to reach herd immunity, she said. “I think it is unlikely that even hard-hit areas in the U.S. have reached that level,” she told The Daily Beast.
Realistically, a vaccine is the only way to safely develop herd immunity for this pandemic. After all, it doesn’t make sense to immunize a herd by making two-thirds of it very sick. “It’s like saying you want to pre-burn 60 percent of your house to keep your house from burning down,” Yang pointed out.
A vaccine isn’t the only way to battle the novel coronavirus, of course. “There is an explosion of information about the virus, and the immune response to the virus,” David Ostrov, a professor in the Department of Pathology, Immunology and Laboratory Medicine at the University of Florida College of Medicine, told The Daily Beast. “Antiviral drug combinations are being developed, and if they are as successful as for HIV and hepatitis C, people should be happy.”
But a safe and effective vaccine should make people even happier. Several leading vaccine candidates are in large-scale, phase-three trials. Health experts expect the first vaccines to be ready for FDA approval by the end of this year or early next year—assuming, of course, the Trump administration doesn’t rush out a vaccine before testing is complete.
In any event, it could take months to immunize enough of the population to effectively suppress the virus. Researchers will need even longer to understand how effective and enduring vaccine-induced immunity might be. “We’ll need to follow people with vaccination to see how fully they’re protected right after they get the vaccine, and then months or years later,” Keith Jerome, a University of Washington virologist, told The Daily Beast.
While all those efforts are underway, individuals and communities will need to continue protecting themselves, including through social distancing. As the Stanford researchers found out, it doesn’t take that many infections, as a share of the population, to wreak an incredible amount of havoc.
