A correction to an earlier version of this article has been appended to the end of the article.

Two more doctors are being investigated by the California Medical Board over allegations they signed unnecessary vaccine exemptions for students, according to court records filed by the board.

The inquiries into Sacramento-area physicians Kelly Sutton and Michael Fielding Allen raise the number to four doctors who are now the subject of ongoing medical board investigations over their exemption practices. A fifth, Kenneth Stoller, is being investigated by the San Francisco City Attorney’s Office.

Together, the five — including Bob Sears of Orange County and Ron Kennedy of Santa Rosa — wrote a third of all exemptions reviewed by this news organization as part of a report on exemptions in eight Bay Area school districts.

Last month, the medical board requested a court order to enforce a subpoena filed to Kaiser Permanente, asking the HMO to turn over copies of medical exemptions signed by Sutton and Allen, as first reported by Kaiser Health News.

The board opened its investigation in response to a tip from the assistant chief of pediatrics at Kaiser’s Roseville Medical Center, who was concerned by medical exemptions the two doctors had signed for the clinic’s pediatric patients, according to court filings.

Kaiser members sought exemptions from Allen and Sutton, neither of whom work for the HMO, and then gave them to their primary care doctors. The medical board initially subpoenaed Kaiser for the records, but the healthcare provider refused to hand over any records that would identify patients. The board is now requesting a court order for the unredacted exemptions.

The medical board recently won a similar court battle to review exemptions signed by Kennedy. In June, just days before Sears argued against stricter student vaccine regulations at a State Assembly hearing, the medical board accused him of writing unnecessary exemptions. His license has been on probation since last year for the same reason.

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Past vaccine disasters show why rushing a coronavirus vaccine now would be ‘colossally stupid’ The investigations are being conducted during the worst measles outbreak in decades, and amid a bitter fight over student vaccine requirements. A bill now in the California Assembly would allow state public health officials to review suspicious exemptions, which a small but vocal minority of Californians argue violates medical freedom.

Sutton and Allen were not immediately available Tuesday for comment.