A nurse prepares a flu shot at the Salvation Army in Atlanta, Feb. 7, 2018. Credit: David Goldman / AP

Three Sanford students reportedly received flu shots without permission from their parents due to school and clinic staff failing to review paperwork adequately.

Sanford school Superintendent Matt Nelson said that two students were vaccinated despite their parents not- or only partially signing permission slips. A parent of a third signed the form but marked the signature “NA,” for “not applicable,” the Portland Press Herald reported.

The school and clinic failed to review the forms well enough, Nelson said.

Nelson’s admission followed confirmation by Northern Light Health, the medical provider for a series of flu shot clinics hosted by the district, that the children got the shots “without fully executed, or completely documented consent.”

The school district hasn’t had issues with its vaccines before, Nelson said. He said that the district’s placing the permission form in a package of back-to-school paperwork this year likely added to the confusion. He declined to say whether the problems occurred at more than one school or to identify the school, citing confidentiality concerns, the Press Herald reported.

It’s not known what ages the children in question are, but George Kimball, the father of a seventh-grader, complained to NBC affiliate News Center Maine about his daughter getting a shot without consent.

“She had the paperwork in her hand and she asked me, ‘Did you sign me up for a flu shot?’ and I said no, and she said, ‘Well I got one,” Kimball told the TV station.

Since Oct. 20, Northern Light Health has had 11 clinics for the Sanford School District. One more is scheduled in November for remote learners.

Adding to the confusion, parents returned forms despite not wanting their children vaccinated. Parents must consent to the injections, but absent a completed form, the district assumes no vaccine is sought.

In some cases, vaccination requests weren’t verified because students returned forms the day of the clinics. Some parents probably found the forms confusing, the Press Herald reported.