St. Joseph Mercy Ann Arbor spokesman Kevin DiCola said six cases are being treated at that hospital.
In all, there are 47 cases in seven states with five deaths. Tennessee, Virginia, Maryland, Florida, North Carolina and Indiana had previously reported cases.
The Michigan Department of Community Health expects the number of cases to rise.
The MDCH said four facilities in the state that received a shipment of the medication involved in the investigation are Michigan Neurosurgical Institute in Grand Blanc; Michigan Pain Specialists in Brighton; Neuromuscular & Rehabilitation in Traverse City; and Southeast Michigan Surgical Hospital in Warren. People who got the shots between July and September could be at risk.