Sen. Rand Paul (R-Ky.) received a sharp education lesson on virus immunity and prevention from Dr. Anthony Fauci during a Senate hearing on Wednesday when the Kentucky physician attempted to attribute New York’s dramatic reduction in COVID-19 cases to herd immunity instead of people following safety protocols.
During a heated back and forth, Paul, who has opposed mask mandates, criticized Fauci’s past praise of New York and its Democratic governor’s handling of the pandemic.
“New York had the highest death rate in the world,” Paul said. “How can we possibly be jumping up and down and saying, ‘Oh, Gov. [Andrew] Cuomo did a great job’? He had the worst death rate in the world.”
Fauci, the nation’s top infectious disease expert, responded with a fact check.
“No, you misconstrued that, senator, and you’ve done that repetitively in the past,” Fauci fired back. “They got hit very badly. They made some mistakes. Right now ... the things that are going on in New York to get their test positivity 1% or less is because they are looking at the guidelines that we have put together from the [coronavirus] task force.”
Those safety guidelines include mask-wearing, social distancing, avoiding crowds, washing hands and participating in public gatherings that are outdoors instead of indoors whenever possible.
“Or they’ve developed enough community immunity that they’re no longer having the pandemic because they have enough immunity in New York City to actually stop,” Paul interrupted.
“I challenge that,” Fauci responded, before repeating the latest data presented by the Centers for Disease Control and Prevention. The CDC’s director, Robert Redfield, was also testifying at the hearing.
“This happens with Sen. Rand all the time. You are not listening to what the director of the CDC said. That in New York it’s about 22%,” Fauci said of the positivity rate. “If you believe that 22% is herd immunity, I believe you’re alone in that.”
To establish herd immunity, a large percentage of a community would have to contract the virus, or a similar one, and produce antibodies to it. Every disease’s threshold for herd immunity is different. In the case of the measles virus, which is one of the most contagious infectious diseases, it’s estimated that 94% of the population would have to be immune to it to achieve herd immunity, according to the Mayo Clinic.
“Experts estimate that in the U.S., 70% of the population — more than 200 million people — would have to recover from COVID-19 to halt the epidemic,” the Mayo Clinic’s website states.
Another report published in the medical journal JAMA in May estimates that to achieve herd immunity for COVID-19, between 55% and 82% of the population would have to have developed antibodies to the virus.
There are some researchers who believe, like Paul, that the percentage necessary to reach herd immunity can be 50% or less. One non-peer-reviewed study from August has estimated that the thresholds for herd immunity can be around 10% to 20% — but as The New York Times pointed out, that belief is in the minority.
Sen. Paul went on to suggest that there may be people out there, about one-third of the population, that have “pre-existing immunity” to COVID-19. This idea is based on these people having what are called cross-reactive antibodies after successfully fighting similar viruses.
Fauci shot that suggestion down too.
“I’d like to talk to you about that also because there was a study that recently came out that pre-existing immunity to coronaviruses that are common cold do not cross-react with the COVID-19,” he said.
Although Fauci did not identify which study he was referring to during his testimony ― nor was he asked ― one published last week in the scientific journal Nature found that “infection with endemic [human coronaviruses] produces little cross-reactivity” to viruses such as the new coronavirus.
Much, of course, remains to be learned about the coronavirus that causes COVID-19. This includes its cross-reactivity with common cold coronaviruses, Eric Topol, the director and founder of the Scripps Research Translational Institute, told The Washington Post.
“While there are a few reports of cross-reactivity of T-cells,” Topol said, specifying the white blood cells that help attack infected cells, “there aren’t neutralizing antibodies (the main defense) or any evidence that this cross-reactivity is playing an important protective role and helping us get to a herd immunity of 70 percent or greater of the population protected.”