Final answer:
Researchers have identified over 200 different strains of HPV, with about 40 causing STIs. At least 14 of these types are oncogenic, with HPV types 16 and 18 linked to 70% of cervical cancers. Vaccines like Gardasil and Cervarix cover several high-risk HPV types, but not all.
Step-by-step explanation:
Researchers have identified over 200 different strains of the human papillomavirus (HPV), with about 40 of them known to cause sexually transmitted infections (STIs). Among these strains, at least 14 oncogenic HPV types are recognized to have a causal relationship with cervical cancers. Additionally, HPV types 16 and 18 are notable for being associated with around 70% of cervical cancers. It is crucial to highlight that, while HPV vaccines such as Gardasil and Cervarix® are effective against several high-risk types of HPV, they do not cover all oncogenic types. Regular screening such as Pap tests and HPV vaccination are the most effective strategies to reduce the risk of HPV-related cancers.