IARC 60th Anniversary - 19-21 May 2026
Session : 20/05/26 - Posters
Vaccine efficacy of a single versus two or three doses of the HPV vaccine: 16 years follow up results.
PIMPLE S. 1, MALVI . 3, PULIKOTTIL E. 4, MUWONGE R. 2, JOSHI S. 5, POLI U. 6, PATEL B. 7, ZOMAWIA E. 8, ANANTHARAMAN D. 9, BHATLA N. 10, SHERPA . 11, LUCAS E. 2, CHANDRASEKHARAN M. 12, BASU P. 2
1 Department of Preventive Oncology, Tata Memorial Hospital, TATA MEMORIAL CENTRE., Mumbai, India; 2 Early Detection, Prevention and Infections Branch, International Agency for Research on Cancer., Lyon , France; 3 Nargis Dutt Memorial Cancer Hospital, Barshi, India; 4 Christian Fellowship Community Health Centre, Ambillikai, India; 5 Jehangir Clinical Development Centre, Pune , India; 6 MNJ Institute of Oncology & Regional Cancer Center, Hyderabad , India; 7 Gujarat Cancer & Research Institute , Ahmedabad , India; 8 Civil Hospital, Aizawl , Aizawl , India; 9 Rajiv Gandhi Centre for Biotechnology , Thiruvananthapuram, India; 10 All India Institute of Medical Sciences, , New Delhi , India; 11 STNM Hospital, Gangtok, India; 12 Karkinos , Mumbai, India
Background
The World Health Organization recommended in 2022 a single-dose of the human papilloma virus (HPV) vaccine, while highlighting the need for long-term follow-up studies to monitor a potential risk of a lower level of protection over time due to waning of efficacy. We report on vaccine efficacy of 1, 2, and 3 doses of the quadrivalent HPV vaccine against HPV infections and cervical precancers at 16 years post-vaccination.
Objective Methods
This multicenter study in India was originally designed to randomize and vaccinate unmarried girls aged 10-18years with either 2 or 3 doses. The order from the Indian authorities to suspend HPV vaccination in trials resulted in the creation of cohorts receiving different doses, including just a single dose. HPV incidence and persistence was evaluated in the cohorts by genotyping cervical samples collected yearly for 4 consecutive years after participants were married. Cervical screening with an HPV test was initiated at age 25 years for married participants. Unvaccinated married women, age- and site-matched, were recruited and compared with vaccinated cohorts. Vaccine efficacy was assessed using proportional incidence ratios.
Results
Of participants 4949, 4980, and 4348 respectively vaccinated with 1, 2 (at 0 and 6 months), and 3 doses, 69%-78% provided samples for genotyping. Proportion of persistent HPV infections for vaccine targeted HPV 16/18 was 0.2 %(95% confidence interval [CI]:0.0-0.3) for Vaccinated group against that of Unvaccinated 2.7% [(, 95% CI 1.9-3.7]. Vaccine efficacy against persistent HPV 16 and/or 18 infections, assessed in 3304 single-dose recipients, was 92.8% (95% confidence interval [CI]: 88.3%- 95.5%); and comparable with those obtained for the 2-dose cohort (94.8%, 95% CI: 90.0% 97.3%) and the 3-dose arm (95.3%, 95% CI: 90.9%-97.5%). No high-grade precancer associated with HPV 16 and 18 was detected among vaccinated participants compared with 9 detected among the unvaccinated women.
Conclusions
Our observational cohort study has established that a single dose of HPV vaccine provides high 16-year protective efficacy against persistent HPV 16 and/or 18 infections and associated cervical neoplasia.