Cancer in the majority of the cases is caused by viral infections. In UK about one in ten cases of cancer could be prevented by vaccination. Cancer of cervix, liver, nasal passages, certain types of lymphoma and rare forms of leukemia are thought to be caused by viruses. Stomach cancer is also linked to a bacterial infection. The Cancer Research Campaign said that viruses can trigger the disease in combination with genetic and environmental effects.
In case of cervical cancer about 99% of sufferers have been infected by the Human Papilloma Virus (HPV). But this virus is present in about 50% of the female population who are carriers of the virus. This virus is sexually transmitted and only 3,000 develop cervical cancer. A vaccine for cervical cancer is under development and expected to be on the market next year. Experts believe it could prevent around 70% of cases of cervical cancer.Dr Anne Szarewski, clinical consultant at Cancer Research UK, said that there are a number of unanswered questions such as the time period of the immunity and if there is a necessity of booster doses. The follow up study for this vaccine has only been four years. A vaccine has also been developed for the Hepatitis B virus which is linked to liver cancer. There are 340,000 cases of primary liver cancer worldwide and about 50% are linked to the Hepatitis B virus.
No vaccines have yet been developed to help combat stomach cancer, nasopharyngeal carcinoma and the lymphomas and leukemias associated with infections. Professor Alan Rickinson, from the Cancer Research UK Institute at the University of Birmingham said that it is important to understand the association between infectious agents and human as it will be useful to break the chain by preventing the infection through vaccination.
