HPV vaccines: so much learnt, so many more lessons to come
Authors: Julia M L Brotherton
Journal: The Lancet Oncology (2015)

The report by Rengaswamy Sankaranarayanan and colleagues 1 Sankaranarayanan R Ramesh Prabhu P Pawlita M et al. for the Indian HPV vaccine study groupImmunogenicity and HPV infection after one, two, and three doses of quadrivalent HPV vaccine in girls in India: early results from a multicentre cohort study. Lancet Oncology. 2015; (published online Dec 1.)http://dx.doi.org/10.1016/S1470-2045(15)00414-3 PubMed Google Scholar in The Lancet Oncology provides new clues as to whether protection against oncogenic HPV infection requires three doses of an expensive vaccine. Previously, outcome data from prospective trials for women who had received only one dose of quadrivalent vaccine has been conspicuously absent by contrast with the data available for the bivalent vaccine. The report by Kreimer and colleagues 2 Kreimer AR Struyf F Del Rosario-Raymundo MR et al. for the Costa Rica Vaccine Trial and the PATRICIA study groupsEfficacy of fewer than three doses of an HPV-16/18 AS04-adjuvanted vaccine: combined analysis of data from the Costa Rica Vaccine and PATRICIA trials. Lancet Oncol. 2015; 16: 775-786 Summary Full Text Full Text PDF PubMed Scopus (226) Google Scholar of data from the large bivalent HPV vaccine trials (PATRICIA and the Costa Rica trial) showed promising results, suggesting that even one dose of bivalent vaccine prevents HPV 16 and 18 infections as effectively as two or three doses do over 4 years. Although the analysis was a post-hoc comparison of women who through circumstance ended up with fewer than three doses, the HPV infection incidence with non-vaccine targeted types suggested an equal risk of new infection in the different dose groups, meaning that the results cannot be explained by confounding. However, given the increased immunogenicity of the bivalent vaccine due to its novel adjuvant, 3 Einstein MH Takacs P Chatterjee A et al. HPV-010 Study GroupComparison of long-term immunogenicity and safety of human papillomavirus (HPV)-16/18 AS04-adjuvanted vaccine and HPV-6/11/16/18 vaccine in healthy women aged 18-45 years: end-of-study analysis of a Phase III randomized trial. Hum Vaccin Immunother. 2014; 10: 3435-3445 Crossref PubMed Scopus (90) Google Scholar whether the surprising effectiveness of only one dose of vaccine is a characteristic of virus-like particle-based HPV vaccines 4 Schiller JT Lowy DR Raising expectations for subunit vaccine. J Infect Dis. 2015; 211: 1373-1375 Crossref PubMed Scopus (66) Google Scholar or at least partly reliant on the immunostimulatory effects of the adjuvant is not possible to discern. Immunogenicity and HPV infection after one, two, and three doses of quadrivalent HPV vaccine in girls in India: a multicentre prospective cohort studyDespite the limitations imposed by the suspension of the HPV vaccination, our findings lend support to the WHO recommendation of two doses, at least 6 months apart, for routine vaccination of young girls. The short-term protection afforded by one dose of HPV vaccine against persistent infection with HPV 16, 18, 6, and 11 is similar to that afforded by two or three doses of vaccine and merits further assessment. Full-Text PDF Open Access