Understanding the human papillomavirus
Prevention and vaccination
HPV vaccinations utilize virus-like particles (VLPs). These VLPs are capsid particles generated from the L1 region of the HPV DNA. The capsid proteins coded for by L1 are highly immunogenic. VLPs are recombinant proteins created in benign biologic systems (such as yeast) and contain no inner DNA core (effectively empty viral capsids) and therefore are not infectious. The L1 gene is incorporated into a plasmid, which is inserted into the nucleus of a eukaryotic cell. Transcription and translation of the L1 gene takes place, creating capsid proteins that self-assemble into VLPs. These VLPs are retrieved and inoculated into candidate patients to illicit an immune response.
Quadrivalent, nine-valent, and bivalent vaccines are available worldwide. However, only the nine-valent vaccine – protective against types 6, 11, 16, 18, 31, 33, 45, 52, and 58 – is available in the United States. This theoretically provides more comprehensive coverage against cervical cancer–causing HPV types, as 70% of cervical cancer is attributable to HPV 16 and 18, but an additional 20% is attributable to HPV 31, 33, 45, 52, and 58. This vaccine also provides protection against the HPV strains that cause genital warts and low-grade dysplastic changes.9
HPV, in most instances, is a transient virus with no sequelae. However, if not cleared from the cells of the lower genital tract, anus, or oropharynx it can result in the breakdown of cellular correction strategies and culminate in invasive carcinoma. Fortunately, highly effective and safe vaccinations are available and should be broadly prescribed.
Dr. Rossi is an assistant professor in the division of gynecologic oncology at the University of North Carolina at Chapel Hill. She reported having no relevant financial disclosures.
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