Vaccine Efficacy Against HPV 16 and 18

There have been safe vaccines for almost two decades to offer protection against human papilloma virus (HPV), a common viral sexually transmitted infection. In some cases, HPV 16 and 18 in particular can cause cervical, anal, penile, oropharyngeal, vaginal, and vulvar cancers. Vaccines could eradicate the vast majority of HPV-related cancer, but currently, there is not nearly enough utilization, especially in low- and middle-income countries (LMICs). An easier HPV vaccine dose schedule would benefit LMICs, in particular, and several recent studies have foreshadowed some possibilities. For example, the Costa Rica Vaccine Trial supported the efficacy of three doses of the bivalent HPV vaccine. A Canadian study found that two doses of the quadrivalent HPV vaccine and two doses plus a booster shot five years later produced similar results. A subsequent analysis of the Costa Rica Vaccine Trial studied participants who received either one dose, two doses, or three doses, and despite fewer detectable antibodies, a single dose against HPV 16 and 18 demonstrates similar protection to two and three doses. Likewise, an Indian trial underscores that one dose of the quadrivalent HPV vaccine is effective. Additionally, an ongoing study presents that Cecolin, a more affordable option, is non-inferior to the quadrivalent vaccine. Taken together, these results signal that a single dose of the HPV vaccine may be sufficient, which may prompt improved vaccination plans for LMICs.