Medical Experts Blast Calif. Coronavirus Herd Immunity Theory

STANFORD, CA — A conservative political columnist and senior fellow at Stanford’s Hoover Institute has advanced a theory in recent weeks that Californians may have developed some degree of herd immunity to the new coronavirus that explains the state’s relatively low case rate compared to other parts of the country.

Victor Davis Hanson’s theory, which Patch reported on earlier this week, has since been subjected to scrutiny from some of the nation's top medical experts.

And so far, it’s not holding up well.

Hanson said in an interview with KSBW and wrote in a National Review column that the virus started in Wuhan, China, months earlier than its government has reported, and that Californians were exposed to the virus earlier than the rest of the country – and New York State in particular – from travelers visiting from China unwittingly carrying the virus.

“That’s overstated. We would be seeing thousands of thousands and thousands of cases if this has been circulating longer,” UCSF infectious disease specialist. Dr. George Rutherford told The San Francisco Chronicle in a report on Hanson’s herd immunity theory in which it interviewed multiple medical experts.

Hanson has no background in epidemiology or biological science according to his bio page, which notes his areas of expertise to be in military history and international conflict.

Hanson’s herd immunity theory has however been embraced by right-wing media as the basis for calling for the cessation of stay-at-home orders mandating strict adherence to social distancing that the vast majority of the country is currently under.

“I maintain to you that it is herd immunity. I think they’ve immunized themselves,” syndicated radio host Rush Limbaugh said on his show in which he interviewed Hanson.

“I think the people in California had this disease in December, January, didn’t know what it was, many people lived through it, got better, built up antibodies before anybody knew what coronavirus was, before anybody knew it had escaped China.”

Credible medical experts are nearly monolithic in their belief that measures such as California’s stay-at-home and the Bay Area’s shelter-in-place orders have dramatically slowed the COVID-19 outbreak and have called for stay-at-home orders to be federally mandated.

According to Slate, which interviewed multiple medical experts in a report on Hanson’s claims: “The theory is appealing to some, particularly those who had respiratory illnesses in late 2019 that they now believe could’ve been COVID-19.

“In their minds, that might mean they have some immunity to the virus—and if a large portion of Americans have some immunity, we can begin our move out of lockdown. But that theory has no scientific basis, and it spreads dangerous misinformation.”

UCSF’s Dr. Charles Chiu, considered to be among the world’s top infectious disease experts, disputed the notion that coronavirus herd immunity exists in California, or anywhere else.

“We’ll still have a largely vulnerable population because people are not immune,” Chiu told the Chronicle. “The only way we’re able to control the virus is with a vaccine.”

Hanson points to reports of an early flu season last year that he believes may have been the coronavirus, unbeknownst to doctors, which he believes supports his theory.

New York State, the epicenter of the outbreak, has reported nearly 20 times as many deaths per 100,000 residents as California according to CNN's latest tally as of Saturday morning.

California has experienced 599 COVID-19-related fatalities in a state of 40 million that's roughly double the population of New York, which has reported 7,887 known coronavirus-related deaths.

"Something is going on that we haven't quite found out yet," Hanson said told KSBW.

Stanford Medicine is conducting a study testing an antibody blood test that Hanson believes will back up his assertion.

Stanford researchers took blood samples from approximately 3,200 volunteers in Santa Clara County it April 2-3 study, The Stanford Daily reports.

Stanford Medicine has distanced itself from Hanson, according to published reports.

Dr. James Zehnder, who helped develop the antibody test, said no relationship exists between Stanford Medicine’s work and the study Hanson cited, according to the Chronicle report.

Slate contacted Stanford Medicine to determine the objectives of the antibody tests and what ties it has to Hanson’s fall coronavirus theory.

“The short answer on the latter is that it doesn’t,” Slate reports.

Stanford spokeswoman Lisa Kim told Slate “Our research does not suggest that the virus was here that early.”

Allison Black, a genomic epidemiologist at Fred Hutchinson Cancer Research Center, which tracks SARS-CoV-2’s genetic code, told Slate that had COVID-19 arrived in the California last fall, we’d have known.

“If it had arrived in fall of 2019, and we were all living our lives as normal, we would’ve had New York back in fall of 2019,” Black said.

But it’s not just right-wing media that have questioned the commonly accepted coronavirus timeline.

Dr. Jeff Smith, Santa Clara County’s chief government executive, told the Los Angeles Times that the coronavirus has been in California longer than previously thought, probably “back in December.”

“This wasn’t recognized because we were having a severe flu season,” Smith said. “Symptoms are very much like the flu. If you got a mild case of COVID, you didn’t really notice. You didn’t even go to the doctor. The doctor maybe didn’t even do it because they presumed it was the flu.”

Smith’s assertion backs Hanson’s theory on the coronavirus timeline.

But no medical experts are known to have publicly backed his theory on herd immunity.

Infectious disease experts told the Chronicle herd immunity requires 40% of a population at the minimum to have immunity.

USCF’s Rutherford told the Chronicle it takes years to build up herd immunity for the flu.

Less than 1% of Californians are known to be infected with the coronavirus according to the Chronicle, although the actual infection rate is believed to be much higher in a state that has one of the nation’s lowest per capita testing rates.

The actual rate is believed to be significantly higher.

Hanson told Fox News’ Laura Ingraham that opponents of President Trump have “weaponized” the coronavirus crisis.

"This crisis has been weaponized," Hanson said. "And it's a tragedy because we're going to come out of it pretty well.

"But there are people who feel that they have to emphasize the downside to enact an agenda that otherwise would not be enacted without this popular depression and anger.”

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This article originally appeared on the Palo Alto Patch