Antibody testing could reveal how widespread coronavirus has been in California

California researchers are looking into how widespread coronavirus is among those who may never have presented with the illness.

Stanford researchers tested thousands of Californians for antibodies, blood proteins that form to neutralize a virus.

A week ago in Santa Clara County, more than 3,200 people were tested for Covid-19 antibodies, according to the Stanford Daily student newspaper.

The researchers’ goal is to determine how many people have these antibodies. Scientists do not know, however, if having had coronavirus already means an individual has immunity.

The virus may mutate into a strain that someone could catch again, for example. Or, like the cold, it could strike again. But Dr. Anthony Fauci told Trevor Noah on Comedy Central that it would be reasonable to believe that this coronavirus could provide immunity in those who have already had the disease.

The results from the Stanford research project are due out any day now.

Eran Bendavid, the study co-lead, told the Stanford Daily that they could be used to guide future public health policy in the country.

“It’s hard to stand up in this epidemic and say, ‘Look, we really don’t know if this epidemic is impending Armageddon,’” Bendavid told the student newspaper. “To know and reduce that uncertainty, you need numbers.”

Layman theories have been floated that coronavirus arrived in California in fall -- although none of these theories have been broached publicly by medical epidemiologists.

Victor Davis Hanson, a senior fellow with Stanford’s Hoover Institute, told the KSBW 8 that he believes it’s possible that Covid-19 was spreading in California in fall 2019. Hanson is a conservative historian not connected with the study. He wrote the Case for Trump.

Hanson told the television station that he believes this because doctors reported an early flu season.

"Something is going on that we haven't quite found out yet," he told KSBW 8. "When you add it all up it would be naïve to think that California did not have some exposure.”

The fact checking site Snopes explores this possibility and says it is unlikely:

"Scientists are not confident they fully understand when or where SARS-CoV-2, the novel coronavirus responsible for COVID-19, first started infecting humans. Does this mean it’s possible you have already had the disease without knowing it? Scientists say that’s quite unlikely, but that gaps in our knowledge about the origin and timing of the pandemic make it impossible to completely rule out at the moment.”

Correction 4/10/2020: An earlier version of this story implied that Victor Davis Hanson was affiliated with the Stanford medical study.