Less than one in ten Americans have coronavirus antibodies, according to the largest study yet of its sort which confirmed that the United States is nowhere close to "herd immunity" despite a strategy pushed by President Donald Trump's newest medical adviser.
Only about 9% of American adults have antibodies to the novel coronavirus, meaning that more than 90% of the country remains at susceptible to infection, according to a study by researchers at the Stanford School of Medicine that was published in The Lancet medical journal.
"This is the largest study to date to confirm that we are nowhere near herd immunity," said Dr. Julie Parsonnet, a professor of medicine and epidemiology at Stanford who co-authored the study.
Experts estimate that 60% to 70% of the population would need antibodies for the country to attain herd immunity, meaning that more than 200 million people would need to be infected and recover. If 200 million people were infected, more than 2 million of those would die given the current US death rate, according to a Washington Post analysis.
Another scientific hurdle to achieving herd immunity is that it is unclear how long coronavirus antibodies last. Scientists estimate that immunity to the coronavirus may only last three to 12 months.
The study comes weeks after Trump added Scott Atlas, a neuroradiologist with no background in infectious diseases who frequently appears on Fox News, to his coronavirus task force. Atlas has drawn public scorn from Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, and Robert Redfield, the head of the Centers for Disease Control and Prevention (CDC), for pushing a "herd immunity" strategy to ease coronavirus restrictions.
The CDC plans to release a study with similar findings in the coming weeks, Redfield said at a Senate hearing last month.
"The preliminary results in the first round show that a majority of our nation, more than 90% of the population, remains susceptible," he said in his testimony.
The Stanford study also found significant disparities by race, income, and population density. More than 16% of Black and Hispanic patients had high antibody levels compared to 4.8% of white patients. People who live in densely populated areas were 10 times more likely to have antibodies than those in rural areas.
There were also massive disparities between states, even those that border each other. More than 33% of New York's population has antibodies, according to the study, compared to 6.4% in Pennsylvania. About 17.5% of Illinois residents have antibodies, compared to only about 3.8% in California.
The study looked at blood samples from more than 28,000 patients receiving dialysis in 46 states. The researchers found that 8% of the patients had antibodies and estimate that the rate is around 9.3% among the general US population.
"Not only is this patient population representative of the U.S. population, but they are one of the few groups of people who can be repeatedly tested," said Dr. Shuchi Anand, the study's lead author, adding that the study found a "higher prevalence of undiagnosed cases consistent with other studies."
Some experts disagreed with the study's approach, arguing that dialysis patients are not representative of the overall population. Dr. John Brownstein, an epidemiologist at the Boston Children's Hospital, told ABC News that dialysis patients are more likely to be unemployed and have less mobility, so they may have been exposed at lower rates. On the other hand, people with underlying health conditions may be more susceptible to the virus.
Still, other studies, including the CDC's, have similar findings. Researchers at University of Washington's Institute for Health Metrics and Evaluation, the Prevention Policy Modeling Lab at Harvard's T.H. Chan School of Public Health, and the University of Minnesota's Center for Infectious Disease Research and Policy estimated that the rate of antibodies in the US is between 9% and 12.5% in three separate analyses, according to The New York Times.
Atlas pushed back on the CDC numbers during a White House briefing last month.
"No, it is not 90 percent of people that are susceptible to the infection," he claimed, adding that immunity from T-cells is a "different type of immunity than antibodies."
Many experts have refuted the idea that T-cells protect people from being infected.
Fauci said it was "extraordinarily inappropriate" for Atlas to contradict Redfield, adding that Atlas "tends to cherry-pick data." He previously criticized Atlas for saying things that are "either out of context or actually incorrect." Redfield was recently overheard on a plane complaining that "everything" Atlas says is "false."
"Dr. Scott Atlas is not an epidemiologist, is not an infectious disease specialist, he has no training in this area at all," Fox News anchor Chris Wallace warned on Friday after Trump and first lady Melania Trump tested positive for the coronavirus. "There are a number of top people on the president's coronavirus task force who have had grave concerns about Scott Atlas and his scientific bona fides."
The Stanford researchers acknowledged that looking only at antibodies has its limitations since some people who are infected do not seem to develop antibodies.
"We don't really have perfect data that antibodies give immunity," Parsonnet told The Washington Post. "And we don't have perfect data that there aren't other forms of immunity that are also important."
But "if these numbers were taken at face value … they still would suggest that there are a lot of people" who have not been infected, Eli Rosenberg, an epidemiologist at the State University of New York at Albany, who was not involved in the study, told the outlet.
Though Rosenberg believes the numbers may not reflect those among the general US population, the findings dovetail with other research, including his own.
"We'd have to experience a lot more illness and death to get to herd immunity and I think it should be morally unacceptable," he told CNBC. "If it took 200,000 deaths to get to something sort of like this, I mean, how many more deaths? We're talking a million or north of a million."
Fauci has repeatedly warned that herd immunity, an increasingly popular concept in some conservative circles' would result in a death toll that is "enormous."
"If everyone contracted it, even with the relatively high percentage of people without symptoms ... a lot of people are going to die," Fauci said in August.
Some conservatives have pointed to Sweden, which largely eschewed lockdowns and restrictions after the pandemic hit, as a model for herd immunity but data shows that is simply not the case. Not only is Sweden's death toll nearly 10 times higher than that of neighboring Norway and Finland, Kaiser Health News noted, only about 7% of residents in the capital of Stockholm and even fewer residents in other cities have tested positive for antibodies.
Several major cities in Spain, which was among the hardest hit countries early in the pandemic, also have antibody rates of less than 10% and are now seeing more infections each day than during their peak in spring.
Researchers at the University of Geneva in Switzerland who reviewed the antibody studies in Europe said in an article in The Lancet that "in light of these findings, any proposed approach to achieve herd immunity through natural infection is not only highly unethical, but also unachievable."
Health and Human Services Secretary Alex Azar vowed to a House committee on Friday that the administration would not pursue a herd immunity strategy despite Atlas' suggestions.
"Herd immunity is not the strategy of the U.S. government with regard to coronavirus," he said. "We may get herd slowing of transmission as we perhaps have seen in the New York area and other concentrated areas. Our mission is to reduce fatalities, protect the vulnerable, keep coronavirus cases down to the lowest level possible."
Experts say that the herd immunity findings show the need for a vaccine before the country can return to normal but the initial vaccines are not expected to provide protection to anywhere near 100% of people who receive it. Redfield has said that masks, as a result, offer better protection against the coronavirus than a vaccine.
"These face masks are the most important, powerful public health tool we have… If we did it for 6, 8, 10, 12 weeks, we'd bring this pandemic under control," Redfield told a Senate committee last month. "I might even go so far as to say that this face mask is more guaranteed to protect me against COVID than when I take a COVID vaccine. Because the immunogenicity may be 70%, and if I don't get an immune response, the vaccine's not going to protect me. This face mask will."