Acute hepatitis B is a contagious short-term illness that occurs within the first 6 months after someone is exposed to hepatitis B.  Acute can sometimes (not always) lead to chronic infection. The younger a person contracts acute hepatitis B, the more likely they are to develop chronic hepatitis B later in life.  Infants exposed to hepatitis B from their mothers at birth have upwards of a 90% risk to become chronically infected.  In adults the risk is considerably smaller at approximately 5% risk to develop chronic hepatitis B.

Cases of acute hepatitis B in Macomb County have been relatively consistent over the last 5 years.  

The rate of acute hepatitis B has decreased by more than 80% nationwide since 1991 when routine hepatitis B vaccination of children was introduced in the United States.