Revac-B Injection 1 ml is used to prevent hepatitis B virus post-exposure. It is given if you have not had previous vaccination, are not properly vaccinated for hepatitis B virus, are vaccinated but ineffective and are at risk of infection. It is also used to prevent infection in infants who are born to a hepatitis-positive mother. It may cause some common side effects like swelling, redness, itching, bruising or hardening of the skin at the site of injection, low blood pressure, headache, dizziness, fast heart rate, vomiting, nausea, joint pains, back pain, fever, tiredness, and chills. Before taking this medicine, you should tell your doctor if you are allergic to any of its components or if you are pregnant/breastfeeding, and about all the medications you are taking and pre-existing medical conditions.