HPV Vaccination Expected to Have Large Impact on Cervical Cancer Rates in the UK
According to the results of a study published in the British Journal of Cancer, vaccinating 12-year-old girls against two high-risk types of human papillomavirus (HPV) could reduce cervical cancer deaths in the UK by 76%.
Human papillomaviruses consist of more than 100 different viruses. Some types of HPV cause warts on the hands or feet; others cause genital warts; and some have been linked with cancer, most notably cervical cancer. The types of HPV most commonly linked with cervical cancer are HPV 16 and HPV 18, but several other high-risk types contribute to cancer as well.
The types of HPV that cause cervical cancer or genital warts are transmitted sexually. HPV infection is extremely common and generally occurs soon after an individual becomes sexually active. Although most infections resolve on their own, some persist and can lead to precancerous or cancerous changes to the cervix, vulva, vagina, penis, and anus.
Recognition of the link between HPV and cervical cancer led to the development of vaccines designed to prevent infection with certain high-risk types of HPV. Gardasil®, developed by Merck, targets HPV types 6 and 11 (which are linked with genital warts) as well as the cancer-associated types 16 and 18. Gardasil was approved by the U.S. Food and Drug Administration (FDA) in June 2006. Cervarix™, developed by GlaxoSmithKline, also targets HPV types 16 and 18.
To explore the potential impact of vaccinating 12-year-old girls against HPV types 16 and 18, researchers in the UK developed a statistical model that incorporated information about likely vaccine effectiveness and current rates of HPV infection and cervical cancer in the UK.
Although the eventual impact of HPV vaccination will depend on several factors, such as vaccine coverage (the proportion of girls who are vaccinated), age at vaccination, and duration of vaccine effectiveness, the researchers’ estimates suggested that vaccination will have a substantial impact on cervical cancer rates in the UK.
In their primary analysis, the researchers estimated that vaccination of all 12-year-old girls would reduce the risk of high-grade precancerous cervical changes by 66% and would reduce the number of cervical cancer deaths by 76%.
The researchers conclude that the public health benefits of HPV vaccination are likely to be substantial in the UK. HPV vaccination, coupled with ongoing cervical cancer screening, is likely to reduce the occurrence of cervical cancer as well as precancerous changes to the cervix. The need for associated diagnostic tests and treatments is also expected to decline.
Reference: Kohli M, Ferko N, Martin A et al. Estimating the long-term impact of a prophylactic human papillomavirus 16/18 vaccine on the burden of cervical cancer in the UK. British Journal of Cancer. 2007;96:143-150.