Nine-valent HPV vaccine effective for more than 5 years
According to a study, the nine-valent Gardasil 9 vaccine is effective in preventing infections caused by all nine human papilloma virus (HPV) genotypes for longer than 5 years. [Lancet 2017 Doi:http://dx.doi.org/10.1016/S0140-6736(17)31821-4]
“Seventy-five years ago, cervical cancer was a very common cause of mortality in the US. Looking forward, with widespread vaccination, it is highly likely that cervical cancer will evolve into historical interest only, and screening, like Pap smears, might go away altogether. HPV vaccines are one of the most scrutinized vaccines ever, but multiple studies have demonstrated the vaccine to be safe and well-tolerated,” said primary author Dr Warner Huh, professor and director of the University of Alabama, Birmingham Division of Gynaecologic Oncology and a senior scientist at the UAB Comprehensive Cancer Center, US.
The study is a follow-up of a previous efficacy and safety study of the nine-valent HPV vaccine published in The New England Journal of Medicine. A total of 14,215 women between the ages of 16 and 26 who were healthy, with no history of abnormal cervical cytology, no previous abnormal cervical biopsy results, and ≤4 lifetime sexual partners, participated in the study. The participants were given three intramuscular injections over a duration of 6 months of either the nine-valent or quadrivalent HPV vaccine.
The older four-valent HPV vaccine called Gardasil is effective against four HPV genotypes: HPV 6, 11, 16 and 18. The newer nine-valent HPV vaccine—Gardasil 9—is effective against the same four genotypes and also an additional five: HPV 31, 33, 45, 52 and 58. According to the study findings, the nine-valent HPV vaccine had 97.4 percent efficacy in the prevention of high-grade cervical, vulvar and vaginal disease associated with the additional five HPV genotypes. Both vaccines were equally effective for HPV 6, 11, 16 and 18, and had similar safety profiles.
The primary outcomes measured in the study were the incidence of high-grade cervical disease, vulvar disease and vaginal disease associated with HPV 31, 33, 45, 52 and 58; and non-inferiority of anti-HPV 6, 11, 16 and 18 geometric mean titres.
Human papilloma virus can cause cervical, vulvar, vaginal and anal cancers. Globally, cervical cancer is the fourth most common cancer in women and in low-income countries, HPV is the cause of nearly all cervical cancers. [Arch Pharm Res 2017. Doi:10.1007/s12272-017-0952-8. Epub ahead of print]
There are three HPV vaccines available in the market, namely Cervarix (bivalent), Gardasil and Gardasil 9. Despite the availability of vaccines, vaccination rates are suboptimal. According to studies, the reasons include a lack of knowledge on the disease and vaccine, and not receiving a recommendation from healthcare practitioner. [Glob Health Action 2016;9(1):29336, J Adolesc Health 2017;61(3):288–293]