UCSF scientists: coronavirus immunity only temporary?

With coronavirus antibodies fading fast, vaccine hopes fade, too

San Francisco Chronicle, by Peter Fimrite, July 17, 2020
Trupti Patil, an associate specialist at UCSF Quantitative Bioscience Institute, conducts research on the virus at Krogan Lab. Photo: Stephen Lam / Special to The Chronicle

Disturbing new revelations that permanent immunity to the coronavirus may not be possible have jeopardized vaccine development and reinforced a decision by scientists at UCSF and affiliated laboratories to focus exclusively on treatments.

Several recent studies conducted around the world indicate that the human body does not retain the antibodies that build up during infections, meaning there may be no lasting immunity to COVID-19 after people recover.

Strong antibodies are also crucial in the development of vaccines. So molecular biologists fear the only way left to control the disease may be to treat the symptoms after people are infected to prevent the most debilitating effects, including inflammation, blood clots and death.

“I just don’t see a vaccine coming anytime soon,” said Nevan Krogan, a molecular biologist and director of UCSF’s Quantitative Biosciences Institute, which works in partnership with 100 research laboratories. “People do have antibodies, but the antibodies are waning quickly.” And if antibodies diminish, “then there is a good chance the immunity from a vaccine would wane too.”

The latest bad news came from scientists at King’s College of London, whose study of 90 COVID-19 patients in the United Kingdom found antibody levels peaked three weeks after the onset of symptoms and then dramatically declined.

Potent antibodies were found in 60% of the patients, according to the study, but only 17% retained the same potency three months later. In some cases, the antibodies disappeared completely, said the study which was published as a preprint Saturday, meaning it has not yet been peer-reviewed.

The report is the latest in a growing chain of evidence that immunity to COVID-19 is short-lived.

A Chinese study published June 18 in the journal Nature Medicine also showed coronavirus antibodies taking a nosedive. The study of 74 patients, conducted by Chongqing Medical University, a branch of the Chinese Center for Disease Control and Prevention, showed that more than 90% exhibited sharp declines in the number of antibodies within two to three months after infection.

There is still hope that the remaining antibodies will bestow some immunity, but infectious disease specialists around the world were surprised and discouraged by the rapid reduction observed in the studies. If the numbers continue dropping after three months, it could mean people will be susceptible to infection by the coronavirus year after year.

Flasks of cell growth medium under a ventilated hood in a tissue culture room at the Krogan Lab.
Flasks of cell growth medium under a ventilated hood in a tissue culture room at the Krogan Lab. Photo: Stephen Lam / Special to The Chronicle

So far, though, there have been only scattered reports of reinfection and no comprehensive studies have verified that it can happen. Experts say the disease hasn’t been around long enough to determine the likelihood of contracting the disease more than once. But other kinds of coronaviruses, like those that cause the common cold, offer clues.

Studies of four seasonal coronaviruses that cause colds show that although people develop antibodies, the immune response declines over time and people become susceptible again. Scientists suspect that the severity of cold symptoms is reduced by previous infections.

“Waning antibodies affect vaccine development,” said Shannon Bennett, the chief of science at San Francisco’s California Academy of Sciences. “Where natural immunity doesn’t really develop or last, then vaccine programs are not likely to be easily successful or achievable.”

Nobody knows yet whether infections by other coronaviruses will help people’s bodies resist COVID-19.

“Our understanding of protective immunity engendered by this virus and how it interacts with past immunity to other coronaviruses is still evolving,”Bennettsaid. “People should not presume they have immunity.”