Background: We estimated the potential impact of an investigational 9-valent human papillomavirus (HPV) vaccine (HPVs 6/11/16/18/31/33/45/52/58) in HPV-related cervical disease in Brazil, Mexico, India and China, to help to formulate recommendations on cervical cancer prevention and control.
Methods: Estimations for invasive cervical cancer (ICC) were based on an international study including 1356 HPV-positive cases for the four countries altogether, and estimations for precancerous cervical lesions were extracted from a published meta-analysis including 6 025 HPV-positive women from the four mentioned countries. Globocan 2012 and 2012 World Population Prospects were used to estimate current and future projections of new ICC cases.
Results: Combined proportions of the 9 HPV types in ICC were 88.6% (95%CI: 85.2-91.3) in Brazil, 85.7% (82.3-88.8) in Mexico, 92.2% (87.9-95.3) in India and 97.3% (93.9-99.1) in China. The additional HPV 31/33/45/52/58 proportions were 18.8% (15.3-22.7) in Brazil, 17.6% (14.2-21.2) in Mexico, 11.3% (7.5-16.1) in India and 11.9% (7.5-17.2) in China. HPV6 and 11 single types were not identified in any of the samples. Proportion of the individual 7 high risk HPV types included in the vaccine varied by cytological and histological grades of HPV-positive precancerous cervical lesions. HPV 16 was the dominant type in all lesions, with contributions in low grade lesions ranging from 16.6%(14.3-19.2) in Mexico to 39.8% (30.0-50.2) in India, and contributions in high grade lesions ranging from 43.8% (36.3-51.4) in Mexico to 64.1% (60.6-67.5) in Brazil. After HPV 16, variations in other majors HPV types were observed by country, with an under representation of HPV 18 and 45 compared to ICC.
Conclusion: The addition of HPVs 31/33/45/52/58 to HPV types included in current vaccines could increase the ICC preventable fraction in a range of 12 to 19% across the four countries, accounting the 9-types altogether 90% of ICC cases. Assuming the same degree of efficacy of current vaccines, the implementation of the 9-valent HPV vaccine in Brazil, Mexico, India and China would substantially impact on the reduction of the world cervical cancer burden.
Keywords: Brazil; China; Epidemiology; Genotype; Human papillomavirus; Human papillomavirus vaccines; India; Mexico; Uterine cervical neoplasms.
Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.