In India, cervical cancer is one of the leading causes of cancer in women, with age-standardized rates (ASR) that vary from 18 to 30 per 100,000. This is in contrast to the United States, where the ASR is as low as 3 per 100,000. The difference is primarily attributable to the availability of screening in the U.S. However, maintaining an effective screening program is difficult and costly: at least $1 billion is spent annually to maintain screening in the U.S. Studies suggest that visual inspection with acetic acid (VIA) or human papillomavirus (HPV)-based screening followed by treatment, may be cost- effective strategies for reducing cervical cancer in India. The availability of two vaccines targeted against HPV types 16 and 18, the two most common cancer-causing types, provides another option. Both vaccines are virus-like particles (VLP) composed of L1, the major capsid protein. Although both have shown significant reductions in type- specific infection and premalignant cervical disease in clinical efficacy trials, limited cross protection against the most closely related types has been reported. Immunogens composed of full-length versions of the minor capsid protein L2 have been shown to induce broad cross-type neutralizing antibodies and may represent an alternative to the highly multivalent L1 VLP vaccines. An Indian company, Shanta Biotech, is currently studying whether a cheap L2 vaccine can be developed that provides broad protection against the >15 HPV types found to be associated with cervical cancer in India. This study will use data from an ongoing NIH funded study in Andhra Pradesh, as well as data from two proposed pilot studies to conduct a cost-effectiveness analysis that compares currently available HPV L1 vaccines to an L2 vaccine. The results of these analyses will be used to inform cervical cancer screening policies in Andhra Pradesh, identify areas of uncertainty that require further study, and provide estimates of L2 vaccine efficacy, duration and cost that can be used to guide clinical trial designs for this vaccine.
This study proposes to use data from an NIH funded study of cervical cancer screening tests in Andhra Pradesh, and new data from 2 proposed pilot studies to develop a combined Markov and HPV transmission model. The combined model will be used to assess the potential cost-effectiveness of an HPV L2 vaccine compared to currently available HPV L1 vaccines. Such a vaccine is currently being developed in India by a local company and has the potential to be cheap and broadly effective in preventing cervical cancer due to multiple high-risk HPV types.
