OCEAN COUNTY, N.J. (CBS) — According to the New Jersey Department of Health, 900 children in the Ocean County area may need to be re-vaccinated. Officials say the vaccines may not have been properly refrigerated.

The department says the children took part in the Vaccines for Children program, a free or low cost program in Ocean County. The federally funded program provides vaccines to low-income children in the state.

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Impacted families whose children were treated at Southern Ocean Pediatrics and Family Medicine in Manahwakin, will receive letters in the mail.

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Issues with the refrigeration temperature were discovered at the facility in July during a compliance visit. At that time, the department stopped shipping VFC vaccines to Dr. Michael Bleiman, who practices at the facility.

On Monday, the state filed a complaint accusing Dr. Bleiman of gross negligence, professional misconduct and others violations.

Parents are warned that children who received these vaccines may not be fully protected against diseases. The vaccines received include measles, mumps, rubella, chickenpox, hepatitis A and B, rotavirus, DTaP/Tdap, Hib, pneumococcal, polio, meningococcal and HPV.

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Parents are encouraged to consult a healthcare professional about revaccination.