San Quentin's suspected hantavirus case was a false positive, officials say

California officials have ruled out a suspected hantavirus case at San Quentin Rehabilitation Center after confirmatory testing came back negative, ending the immediate health scare at the state prison.

The inmate's first result came from a commercial antibody test, which can sometimes produce false positives. Additional PCR testing by the state public health lab ruled out infection, according to reporting cited by California officials.

How the case unfolded

The concern surfaced last week after an inmate at San Quentin was being evaluated for possible hantavirus. Earlier reporting said the person was in stable condition and that the area where the inmate had been housed was decontaminated while state and federal health authorities reviewed the samples.

At the time, the California Department of Corrections and Rehabilitation said there was no confirmed infection at the prison. The later PCR result closed the loop and cleared the case as a false alarm.

Why the testing mattered

Hantavirus is a rare but potentially deadly rodent-borne disease that can affect the lungs. Because antibody screening tests can cross-react with other viral infections, health officials rely on confirmatory testing to distinguish a suspected exposure from a real infection.

The false-positive result is a reminder that an initial screening test does not always mean a patient has the disease, especially when public health teams are investigating a high-concern pathogen.

What happens next

No confirmed hantavirus case remains at San Quentin based on the information released so far. Further monitoring would depend on whether officials disclose new symptoms or new exposures.

California health officials have also been watching some residents exposed in the recent MV Hondius Andes-hantavirus outbreak, which helped keep attention on the San Quentin investigation as it developed.