HALIFAX -- Health officials in Halifax are advising 500 patients of a suspended doctor that they may have to be re-vaccinated.

The College of Physicians and Surgeons of Nova Scotia says it suspended Dr. William Vitale for improperly administering vaccines to children before 24 months of age from 1992 to 1994 and from 2003 to 2013.

The Capital District Health Authority's medical officer of health, Dr. Robin Taylor, says while there is no emergency, patients are being advised to have their first re-vaccination appointment by the end of February.

In a news release, the Nova Scotia government says affected patients were supposed to have received the vaccines in separate doses at the ages of two months, four months, six months, 12 months and 18 months, but instead received mixed and incompatible vaccines in a single shot.

Those affected will be notified by mail where possible, while patients in the Halifax area who are without a family doctor will be able to get their shots at a vaccination clinic beginning Jan. 8.

Officials say it may take more than six months to fully immunize a patient against some diseases.

The government says vaccination protect people against diseases, such as measles, mumps, tetanus and whooping cough.