New London — An administrative error enabled nearly a dozen faculty and staff at The Williams School to get COVID-19 vaccinations last week even though the shots are so far being reserved for health care personnel and residents of long-term care facilities.

Williams Head of School Mark Fader said Monday the U.S. Centers for Disease Control informed the school late last month— mistakenly, it turned out — that its employees were eligible for the vaccinations being administered as part of "Phase 1a." Following protocols, he said he directed an assistant to provide a roster of Williams employees via the Vaccine Administration Management System, or VAMS, a web-based application that states are using to help track the vaccine’s rollout.

Each of the private school’s 53 employees received an email providing instructions on scheduling a vaccination, Fader said, but then Ledge Light Health District, the local health department for nine towns in the area, contacted the school Dec. 29 to say the initial VAMS email had been sent to “the wrong organization.”

Williams, a private college preparatory day school for grades 6 through 12, is located on the Connecticut College campus.

“Your organization has been identified as a critical infrastructure group by your state,” the VAMS email to Williams’ COVID-19 coordinator, Fader’s assistant, begins. “This means your employees are eligible for a COVID-19 vaccine.”

In an email sent Monday night, a spokeswoman for the state Department of Public Health confirmed the department uses VAMS.

"I don't know the particulars of what happened with the Williams School, but we are grateful they realized the mistake and quickly took corrective action," Maureen Fitzgerald, the spokeswoman, wrote.

Fader said the school immediately emailed its employees about the mistake and advised them to cancel any appointments they had made for vaccinations. At that point, 11 staff members already had gotten the vaccine, he said.

"By the time I read my email and went to sign up, I couldn't get an appointment," Fader said.

Stephen Mansfield, Ledge Light’s director of health, said he brought the misclassification of The Williams School employees to light after hearing from a colleague that a number of them had shown up at a clinic for vaccinations. The colleague was from the Mansfield-based Eastern Highlands Health District, which serves 10 towns in Tolland and Windham counties.

Mansfield said the mix-up involving The Williams School is not an isolated incident.

“The breakdown occurred where someone entered individuals into the system who weren’t eligible,” he said. “It was an honest mistake. (The school) was very apologetic. ... We do our best to communicate to our partners what the eligibility requirements are, but it isn’t always crystal clear.”

While the state has yet to issue detailed guidance about who will be eligible to receive the COVID-19 vaccine in "Phase 1b," the CDC has projected that the phase will include those who work in the education sector (teachers and support staff members) as well as such frontline essential workers as firefighters and police officers; corrections officers; food and agricultural workers; and public transit workers.

Connecticut, which as of Monday had administered more than 75,000 doses of the vaccine, expects to complete its Phase 1a inoculations by the end of the month.

Fader said the 11 Williams employees who received the COVID-19 vaccine will be allowed to get the second dose that is part of the two-dose regimen for the versions manufactured by both Pfizer and Moderna. He said he was not authorized to release information about how many of those vaccinated were faculty and how many were staff.

“We have followed all protocols from CDC/Ledge Light Health District throughout the pandemic, which has allowed us to fortunately stay open for in-person learning each day, five days a week,” Fader wrote in an email.

b.hallenbeck@theday.com