Herd Immunity Study Rand Paul Cited Against Fauci Actually Refutes Senator's Claim

After clashing with Anthony Fauci on herd immunity at a senate hearing, Senator Rand Paul tried to back up his claims with a study that looked at the level required for this to be achieved in a community. However, the findings of the paper refuted Paul's claims and instead provided support to the infectious disease expert.

Fauci and Paul appeared at a senate hearing Wednesday where Fauci praised New York for getting coronavirus cases under control and keeping numbers low ever since.

Following the exchange, Paul posted a link to a study published in Science that found around 40 percent of a population would need to be infected to achieve herd immunity. But as a number of scientists pointed out, this is double the level of infection seen in New York City.

At the start of the pandemic, the state of New York was hit hard by the virus, with a massive spike seen across April and May. At its worst, over 10,000 cases were being recorded daily.

However, the following month there was a sharp downturn and since the middle of June, new cases have remained steady, generally hovering at between 500 and 1,000 per day. Of the almost 452,000 cases in the state, 366,000 were recorded before June.

At the hearing, Paul appeared to criticize the director of the National Institute of Allergy and Infectious Diseases for praising New York's efforts to control the disease. "You've been a big fan of [New York Governor Andrew] Cuomo and the shutdown in New York," he said. "You've lauded New York and their policies. New York had the highest death rate in the world."

Fauci responded to Paul to say the senator had "misconstrued" the situation in New York and that while "some mistakes" were made, the state has managed to get its test positivity rate down to below 1 percent by following guidelines set out by the White House coronavirus task force.

Paul then came back to say the reason New York case numbers are now low is that the state had such a high level of infections it reached herd immunity. This is where the level of infection in a community is so high the virus is not able to spread effectively. "I challenge that senator," Fauci replied. "In New York, it's about 22 percent [immunity]. If you believe 22 percent is herd immunity, I believe you're alone in that."

On Thursday, Paul tweeted a link to a study that he said shows how herd immunity can be achieved with less than two thirds of the population getting infected. "Dr. Fauci—this article in Science proposes that heterogeneity of human populations allows for non-random transmission where immunity concentrates in younger less vulnerable members of the population," he wrote. "Therefor herd immunity may occur at less than 2/3rds."

However, the paper, published August, found that the minimum level of infection required for herd immunity was around 40 percent. This is far higher than the known infection rate in New York. One preprint paper posted at the end of June found around 19 percent of people in New York City had been infected with SARS-CoV-2, the virus that causes COVID-19. The former U.S. Food and Drug Administration commissioner Scott Gottlieb told CNBC that around a quarter of the city's population had been infected.

The disparity between these figures was pointed out by Ashish K. Jha, Dean of the Brown University School of Public Health. Writing on Twitter, he said: "Senator Paul uses this article to show he was right. But [the] article actually proves the opposite."

"Paul links to [an] article which shows that with heterogeneous mixing, [herd immunity] may be achieved at 43 percent," he wrote, saying these findings were "possible."

"[The study] actually disproves Senator Paul's own point that NY hit herd immunity. Bottom line: article linked by Paul actually supports Fauci's point that NY [is] unlikely to have [herd immunity]."

Senator Rand Paul has been contacted for comment.

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Rand Paul at a hearing on September 24, 2020. The senator clashed with Anthony Fauci Wednesday over New York's handling of the coronavirus pandemic. Tom Williams - Pool/Getty Images
Herd Immunity Study Rand Paul Cited Against Fauci Actually Refutes Senator's Claim | Health