Clinics of Columbia Park Medical Group (CPMG) in the cities of Andover, Columbia Heights and Fridley, Minnesota are giving free revaccination to 4,500 patients who received ineffective vaccines from October 2006 to August 2007.

The CPMG on Tuesday sent letters to the affected patients telling them to get new shots against rotavirus, hepatitis A and B, pneumonia, tetanus, typhoid and rabies at the said clinics on Dec. 15, 20 and 29.

The CMPG also apologized to the patients. WCCO quoted Dr. Tom Rolewicz, CPMG's Chief Medical Officer, as saying in a letter, ""Patient safety is always our top priority, and we are committed to correcting this situation in the best health interests of our patients."

Officials of the Minnesota Department of Health and CPMG recommended the revaccination after they discovered during a routine audit that vaccines given to the said patients were stored in the wrong temperature rendering these ineffective.

The notification of the patients was delayed because CPMG took time to identify those who needed to retake the vaccines and to prevent patients from suffering side effects if they get another shot to soon.