1. Poster template by ResearchPosters.co.za The efficacy of bivalent and tetravalent HPV vaccination against cervical intraepithelial neoplasia and persistent HPV 16 and 18 infection Huma Riaz, University of Aberdeen INTRODUCTION Cervical cancer, the second leading cause of death from cancer in women worldwide, is caused by infection with oncogenic types of human papillomavirus (HPV). Annually, there are 493 000 new cases diagnosed worldwide. The high risk regions are Eastern and Western Africa (ASR greater than 30 per 100 000, Southern Africa (26.8 per 100 000), South-Central Asia (24.6 per 100 000), South America and Middle Africa (23.9 and 23.0 per 100 000, respectively) 1,2. The various histological cancer types are preceded by dysplastic lesions (cervical intraepithelial neoplasia [CIN] grades 1 to 3) 3,4. Although screening programs using the Papanicolaou (Pap) test have led to significant reduction in mortality, approximately 230 000 women per year die of cervical cancer worldwide, with 80% occurring in developing countries 5,6. HPV 16 and HPV 18 infections are responsible for approximately 70% of all invasive cervical cancers 7. Two HPV vaccinations targeting these have been developed; a bivalent and a tetravalent vaccine. The bivalent vaccine targets HPV types 16 and 18, whereas, the tetravalent vaccine targets HPV types 6, 11, 16 and 18 8. OBJECTIVE METHOD Bibliographic search on databases to identify double blind placebo RCTs. Pooled percentage efficacy and meta- analyses were conducted for the following regimens/infections: bivalent AND tetravalent anti-HPV vaccination for CIN 1 to 3, persistent HPV 16 and HPV 18 infection and tetravalent anti-HPV vaccination for persistent HPV 16 and HPV 18 infection. SPSS 19 and BioStatXL were used for data tabulation and for Forest plots. RESULTSDISCUSSION Safety and Efficacy HPV vaccinations are highly effective in reducing persistent infection with HPV 16and 18, which are the main viruses leading to cervical cancer as well CIN 1 to 3. The vaccine is effective up to 7.3 years provided that all the doses are administered as per protocol. Safety studies highlight that the most common side effects experienced were not different to those experienced by any vaccination. The Public Health Agency of Canada (PHAC) reported 407 adverse events in February 2009, none being serious or life threatening. Cervical screening remains the gold standard prevention for women over 30 years of age. Acceptance and Awareness HPV vaccines are highly effective in girls of adolescence who have had no prior exposure to the infection or sexual activity. Given the very young recommended age - parents and religious authorities may believe that giving a vaccine for STI’s may encourage young people to be promiscuous or argue that their children will not be sexually active before marriage, hence will not need the vaccination. Affordability Provided that the cost per vaccinated girl is less than that in developed countries, vaccination programs can be very cost effective. However, despite being cost effective, the vaccines are not necessarily affordable. It is imperative, therefore, that the Global Alliance for Vaccines and Immunisations alliance associated countries are subsidised as the vaccines will only be cost effective when the dose prices are $1-$2. RESOURCES Figure 1: Meta-analysis showing a reduction of risk in CIN 1 in the vaccination cohort [RR 0.072 (95% CI 0.036-0.144)], thus favouring it over placebo. Figure 2: Meta-analysis showing a reduction of risk in CIN 1 in the vaccination [RR 0.025 (95% CI 0.07-0.081)], thus favouring it over placebo. Figure 3: Meta-analysis showing a reduction of risk in CIN 1 in the vaccination cohort [RR 0.076 (95% CI 0.038-0.153)], thus favouring it over placebo. Figure 4: The percentage efficacy of the bivalent and tetravalent vaccine against CIN 1 to 3 and persistent HPV i16 and 18 infection. To perform a pooled analysis of randomised controlled trials on vaccine efficacy in preventing cervical persistent infection and CIN 1 to 3. Schiffman M, Castle PE. The promise of global cervical-cancer prevention. N Engl J Med 2005 Nov 17;353(20):2101-2104. Mukhopadhyay P, Paul B. Introducing HPV Vaccine in Developing Countries - Addressing the Challenge. Indian J Community Med 2009 Oct;34(4):370-371. Goldie SJ, O'Shea M, Diaz M, Kim SY. Benefits, cost requirements and cost- effectiveness of the HPV16,18 vaccine for cervical cancer prevention in developing countries: policy implications. Reprod Health Matters 2008 Nov;16(32):86-96.