In May 2016, Mr. A – as he is called in a charging document – emailed Dr. Tara Zandvliet interested in a medical exemption from vaccinations for his child.

“If you can find four or more people affected with [the type of illnesses listed on my webpage], I could make a case that she likely has inherited a tendency to over reactive immune system,” Zandvliet responded. The doctor was probing for a family history that might show higher incidents of autoimmune disorders.

The Centers for Disease Control and Prevention and the American Academy of Pediatricians do not recognize family history of autoimmune conditions as a legitimate reason to avoid vaccination. But Zandvliet has written many dozens of vaccine exemptions for similar reasons, Voice of San Diego revealed in March. The investigation showed that Zandvliet had written nearly a third of all medical exemptions for San Diego Unified School District.

Zandvliet ultimately granted an exemption to Mr. A’s daughter. But in doing so, she did not follow the standards of care she lays out on her own website, according to the charging document. She granted the exemption based largely on family letters, instead of medical documentation. And she granted it based on qualifying illnesses, which she later removed from her website, after being questioned by Voice of San Diego in March.

The state attorney general charged Zandvliet with gross and repeated negligence, as well as failure to properly maintain records for writing the exemption. If she is found to have improperly issued the exemption, the Medical Board of California will ultimately decide her punishment. She could lose her medical license, be suspended or put on probation.

Zandvliet is not criminally charged and is allowed to continue practicing medicine while the case is pending. If it goes to trial, it will be heard by an administrative law judge.

Only one physician, Dr. Bob Sears of Orange County, has been sanctioned for improperly writing a vaccine exemption. Sears, who came to prominence as a vaccine skeptic, is still on probation for gross negligence and now faces new charges for improperly writing exemptions. The new charges are still pending.

The charges against Zandvliet are identical to those Sears faced in the case that landed him on probation. One other physician, Dr. Kenneth Stoller, is also facing gross negligence charges for vaccine exemptions.

In the charging document, Zandvliet admits she has likely written 1,000 vaccine exemptions since 2015, when a state law went into effect banning personal belief exemptions to vaccines.

Zandvliet charges $180 for an office visit related to a vaccine exemption. Not counting exemptions she may have declined to write, she has made roughly $180,000 in the vaccine exemption business.

A new law, partially inspired by VOSD’s investigation, would subject doctors like her to more scrutiny. Starting in 2021, public health officials will have the power to review and overrule any exemption written by a physician who wrote more than five exemptions in a calendar year.

After Zandvliet emailed Mr. A – whose name is withheld in the document to protect patient privacy, according to the charging document – he managed to find four accounts of family members with autoimmune conditions. But he only provided medical documentation for one. In the other three cases, he simply provided Zandvliet with letters from family members.

Zandvliet’s own website suggests she will not write an exemption based on such thin documentation. “Useful but rarely sufficient are emails or letters from family members about their diseases,” the website reads.

The three letters cite psoriasis and asthma as the primary conditions. After questioned by Voice in March about the reasons she uses to issue an exemption, Zandvliet removed psoriasis and asthma (as well as eczema) from her website as qualifying conditions in family history that might lead her to write an exemption.

At the time she said: “I have found that a few of the diseases on my list seem to invite misinterpretation more than others, and so I have deleted them.”

Zandvliet did not respond to a request for comment about the new charges.

Dr. Mark Sawyer, an infectious disease specialist at Rady Children’s Hospital, previously told Voice of San Diego that Zandvliet and other physicians like Sears were writing exemptions for “soft reasons.” There is no proof whatsoever that a family history of autoimmune conditions or allergies makes a person more likely to have an adverse reaction to a vaccine, he said.

But Sawyer noted that Zandvliet or Sears could easily design a study to test their hypothesis.

The charging document lays out Zandvliet’s reasoning on family history: “A consistent pattern of multiple people with an overactive immune system. (sic) That would give me an indication that, when I give a vaccine, they are a slightly higher risk of overreaction to the vaccine. Not necessarily a horrible one, but slightly higher risk.”

This notion that family history of immune conditions might “slightly” increase a child’s chances of an adverse reaction to vaccines line up with past statements Zandvliet made to VOSD about her reasoning for granting exemptions.

When issuing the exemption, however, Zandvliet moved away from her use of the word “slight.”

“I feel she is at high risk of a severe reaction to vaccines,” Zandvliet wrote in the patient’s exemption letter. “This medical exemption for vaccines is permanent.”

All this hypothesizing about whether the child might be able to safely receive a vaccine turned out to be unnecessary. Mr. A’s daughter had previously received some vaccinations and had no adverse reaction, according to the charging document. During the child’s visit, Zandvliet did not inquire as to whether the child had been previously vaccinated, so she was unaware, according to the charging document.