Research Spotlight

A prospective cohort study comparing efficacy of 1 dose of quadrivalent human papillomavirus vaccine to 2 and 3 doses at an average follow up of 12 years postvaccination

JNCI Monographs| 12 November 2024 | doi.org/10.1093/jncimonographs/lgae042

Sylla G Malvi, PhD, Pulikkottil O Esmy, MD, Richard Muwonge, PhD, Smita Joshi, PhD, Usha Rani Reddy Poli, DNB, Eric Lucas, MSc, Yogesh Verma, MD, Pesona Grace Lucksom, MD, Anand Shah, MD, Bijal Patel, MD, Eric Zomawia, MD, Sharmila Pimple, MD, Kasturi Jayant, MSc, Sanjay Hingmire, MBA, Aruna Chiwate, CT (IAC), Uma Divate, MD, Shachi Vashist, BHMS, Gauravi Mishra, MD, Radhika Jadhav, MSW, Maqsood Siddiqi, PhD, Catherine Sauvaget, MD, Subha Sankaran, MCA, Thiraviam Pillai Rameshwari Ammal Kannan, MSc, Surendra S Shastri, MD, M Radhakrishna Pillai, FRCPath, Devasena Anantharaman, PhD, Neerja Bhatla, MD, Rengaswamy Sankaranarayanan, MD, Partha Basu, MD

ABSTRACT

Background

While recommending a human papillomavirus (HPV) single-dose vaccination schedule in 2022, the World Health Organization highlighted the need for long-term follow-up studies to monitor waning of protection. We report on vaccine efficacy against HPV infections in 1-, 2-, and 3-dose schedules and protection against cervical precancers at a median follow-up of 12 years postvaccination.

Methods

This randomized multicenter study in India was originally designed to vaccinate unmarried girls aged 10-18 years with either 2 or 3 doses of quadrivalent HPV vaccine. A ministerial decree to halt vaccination in trials resulted in the creation of cohorts receiving different doses, including just a single dose. Cohorts were assessed for incident and persistent infections 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. Age- and site-matched unvaccinated married women were recruited to be compared with vaccinated cohorts. Vaccine efficacy was assessed using proportional incidence ratios.

Results

The number of participants in the 1-, 2- (at 0 and 6 months), and 3-dose cohorts was 4949, 4980, and 4348, respectively. Of the recipients, 71%-82% in the different cohorts were eligible to provide samples for genotyping. Vaccine efficacy against persistent HPV 16 and 18 infection was 92.0% (95% confidence interval [CI] = 87.0% to 95.0%) in 3022 recipients of the single dose; and comparable with that observed in the 2-dose arm (94.8%, 95% CI = 90.0% to 97.3%) and the 3-dose arm (95.3%, 95% CI = 90.9% to 97.5%). No high-grade precancer associated with HPV 16 and 18 was detected among vaccinated participants compared with 8 precancers detected among the unvaccinated women.

Conclusion

This observational cohort study has established that a single dose of HPV vaccine provides high protective efficacy against persistent HPV 16 and 18 infections and associated neoplasia 15 years postvaccination.