Kaiser Permanente has called on regulators to investigate Santa Clara County’s coronavirus vaccine distribution, claiming local health officials ran afoul of the law when they canceled appointments for thousands of members of the Bay Area hospital chain.

The Oakland-based healthcare network spelled out its grievances in a lengthy series of tweets over the past few days, announcing that it filed a complaint with the U.S. Department of Health and Human Services over the county’s alleged wrongdoing.

In a Twitter thread Saturday, the hospital chain slammed the county for “unilaterally” canceling second doses for 7,556 Kaiser members, calling it a “direct violation” of U.S. Centers for Disease Control and Prevention (CDC) rules prohibiting vaccine providers from denying vaccination based on recipients’ “coverage or network status.”

Kaiser Permanente learned late Thursday that Santa Clara County unilaterally cancelled second dose vaccine appointments for 7,556 individuals because they were Kaiser Permanente members.

— KP Santa Clara (@KPSantaClara) March 20, 2021

Kaiser officials called the county’s explanation for the sudden cancelations “grossly misleading,” saying most vaccine providers allocate both first and second doses “to ensure we can fulfill our commitment to every person we vaccinate.”

The County’s explanation of why it cancelled second dose appointments is grossly misleading. Kaiser Permanente and most other vaccine providers allocate vaccine we receive to both first and second doses to ensure we can fulfill our commitment to every person we vaccinate.

— KP Santa Clara (@KPSantaClara) March 20, 2021

“By contrast,” the Twitter thread went on to say, “Santa Clara County has created this issue for itself and thousands of its vaccine patients by not accounting for second doses.”

The County’s assertion that Kaiser Permanente approved cancelling these appointments is false.

— KP Santa Clara (@KPSantaClara) March 20, 2021

Under state and federal rules, Kaiser wrote, vaccines are allotted so that first and second doses ship to the same vaccination location.

“So,” the hospital company continued, “Santa Clara County received the doses for these Kaiser Permanente members’ second vaccinations but chose to give them to others, targeting individuals with Kaiser Permanente coverage for cancelation.”

Kaiser officials said they told the county that all its vaccines were already booked out, to members and non-members alike, and that the company had none left to allocate.

Further, the hospital chain alleged, the county lied to patients about having coordinated the mass cancelations with Kaiser.

“In fact,” Kaiser stated in the same weekend Twitter thread, “the county initially failed to send us the names of the patients whose appointments they had cancelled, which risked leaving these thousands of people in confused limbo.”

County officials denied doing anything wrong, saying it was “forced” to transfer several thousands of appointments back to Kaiser.

“We know this situation has created many challenges for the patients whose appointments were transferred, and of course the county did everything it could to avoid this situation,” public health spokespeople told San Jose Inside in an email.

They added: “But the county was surprised by the tone and inaccurate content of Kaiser’s recent public statements, particularly after Kaiser declined the county’s request for Kaiser to transfer excess doses of vaccine to the county so it would have the supplies needed to continue serving Kaiser these members. The county had previously provided Kaiser 8,000 doses of vaccine when it faced a similar shortage, and Kaiser declined to reciprocate even though it had adequate vaccine inventory to do so.”

Kaiser’s claims that the county violated CDC rules “is false,” officials said.

“The county has gone to extraordinary lengths to ensure robust access to vaccination for all county residents, including for Kaiser members when Kaiser did not offer those members appointments itself,” county officials wrote.

“And unlike Kaiser, the county has focused particularly on community members who have been disproportionally affected by Covid-19.”

Kaiser concluded its Twitter thread over the weekend by saying about a quarter of the 400,000 vaccinations its administering each week are going to non-members, that it’s “steadfastly committed to fighting this crisis together” and that it hopes the county returns to “a collaborative approach.”