Oncovac Vaccine is a medicine used for treatment of early-stage bladder cancer. It is recommended for people with early bladder cancer that has not yet reached the bladder muscle. It kills the cancer cells and reduces the risk of cancer coming back again (recur). Oncovac Vaccine is administered by a healthcare professional. It is instilled directly into the bladder through the urethra. For it to be effective, you should complete the course of the vaccine. You should not discontinue even if you get better until the course is completed. Some common side effects of this medicines include difficulty in urination, urinary tract infection, and fever. These are usually mild and go away with time. However, if they persist or get worse, you should let your doctor know. Before receiving the vaccine, you should let your doctor if you have ever had an allergic reaction to any vaccine. Also tell your doctor if you have any problems with your heart, kidneys, or liver. Some other medicines may react with this vaccine, so let your doctor know of all the medication you are taking. Pregnant or breastfeeding should consult their doctors first before receiving this vaccine.