One of the most common side effects of a hepatitis shot is pain or soreness where the injection was given. Other side effects include fever, fatigue, loss of appetite, and headache. More seriously, a person may experience an allergic reaction to the hepatitis shot. Hepatitis shots can help prevent certain types of viral hepatitis, which is a serious medical condition in which the liver becomes inflamed.
Most side effects of a hepatitis shot are mild. Both the hepatitis A and B vaccines can result in pain where the injection was administered. The frequency of this side effect can vary, depending on which hepatitis shot was administered. Half of all adults and one in five or six of children experience pain with a hepatitis A shot. In contrast, 25 percent of people experience pain with the hepatitis B shot.
Side effects associated with the hepatitis A shot occur about three to five days after the shot was administered and can continue for about one or two days. After receiving the hepatitis A shot, one in six adults and one in 25 children may experience a headache. Some children have reported losing their appetites, and one in 14 adults may feel tired. Patients may also experience a low fever.
For some patients, the hepatitis A shot may cause an allergic reaction, which can occur within a few hours of the shot. Some symptoms of allergic reactions are a high fever, changes in behavior, hives, and pale pallor. A person may also experience wheezing or have trouble breathing. They also may have an increased heart rate, dizziness or general weakness. Since a person can react to any portion of the hepatitis shot, he should not risk taking it if he is allergic to any of the ingredients. If there are any signs of a reaction to a hepatitis shot, a person should seek medical attention immediately.
In contrast with the hepatitis A vaccine, the common side effects for the hepatitis B vaccine are relatively few. A person receiving this shot may have a one in 15 chance of experiencing a mild to middle grade fever, which can reach 99.9 Fahrenheit (37.7 Celsius) or higher. Allergic reactions to the hepatitis B vaccine may also occur, but these are rare, affecting just one person in more than a million.