One of the few vaccines that can actually protect against cancer is the human papillomavirus (HPV) vaccine, which prevents four strains of HPV. But some parents have expressed concerns about the safety of the HPV vaccine.

People living with HIV (human immunodeficiency virus) are at greater risk of various forms of cancer. In fact, when these cancers appear, it means the virus has turned into full-blown AIDS (acquired immunodeficiency syndrome).