Undeniably, cervical cancer represents a major global health challenge. Therefore, finding ways to improve the reach of preventive measures like the Human Papillomavirus (HPV) vaccine is critical. A landmark clinical trial examined the efficacy of a single-dose HPV vaccine regimen against the established two-dose schedule. The study’s primary goal was to determine if one dose was noninferior to two doses in preventing persistent HPV type 16 or 18 infection over a four-year period. Researchers enrolled over 20,000 girls aged 12 to 16 years, randomly assigning them to receive one or two doses of either a bivalent or a nonavalent vaccine.
The trial’s findings offer strong support for simplifying the vaccination schedule. Specifically, the noninferiority analysis demonstrated that one dose successfully matched the protection offered by two doses in preventing HPV16 or HPV18 infection. The rate difference for the bivalent vaccine was -0.13 infections per 100 participants, while for the nonavalent vaccine, the rate difference was 0.05 infections per 100 participants. Neither of these findings crossed the prespecified noninferiority margin, thereby confirming the regimen’s effectiveness. In addition, the overall vaccine effectiveness against persistent infection with HPV16 or HPV18 was high, with the single bivalent dose showing 94.6% effectiveness and the single nonavalent dose showing 97.5% effectiveness. Consequently, a single-dose regimen could dramatically streamline global vaccination efforts.
Impact of Single-dose HPV Vaccine on Indian Public Health
Cervical cancer is a pressing public health concern in India, accounting for a significant portion of the global disease burden. Therefore, adopting a simplified schedule carries immense programmatic value. The World Health Organization (WHO) and its Strategic Advisory Group of Experts on Immunization (SAGE) have already endorsed a one- or two-dose schedule for the primary target group of girls aged 9–14 years. Furthermore, Indian public health bodies recognize the benefit of this shift. Specifically, the National Technical Advisory Group on Immunisation (NTAGI) has recommended a single-dose HPV vaccine for introduction into the Universal Immunization Program (UIP) for girls aged 9–14 years.
Moreover, local evidence corroborates the international trial data. For instance, long-term studies conducted in India have already shown durable protection from a single dose against high-risk HPV types 16 and 18, comparable to multi-dose schedules, even after a follow-up of over 10 years. Consequently, a national single-dose HPV vaccine program is projected to prevent close to one million cervical cancer cases over the lifetime of young birth cohorts. Implementing this efficient strategy is critical for India to achieve the WHO’s cervical cancer elimination target of 90% vaccination coverage by 2030.
Safety and Programmatic Implications
The trial’s safety profile showed that the rate of adverse events was similar between the one-dose and two-dose groups across both vaccine types. Therefore, the data supports the safety of the reduced regimen. Programmatically, simplifying the dosing schedule from two doses to a single dose offers several immediate benefits. Firstly, it drastically reduces vaccine cost per fully vaccinated individual. Secondly, it eases the logistical burden associated with recalling recipients for a second appointment, a major barrier to high coverage in low- and middle-income countries. Thus, the finding provides a powerful tool for health systems to scale up vaccination and improve health equity across diverse populations. The global public health community views this data as a critical step toward achieving cervical cancer elimination.
Frequently Asked Questions
Q1: What does “noninferiority” mean in this HPV vaccine study?
Noninferiority means that the single-dose regimen was proven to be no worse than the two-dose regimen by more than a very small, predefined margin (1.25 infections per 100 participants in this trial). The results confirmed that the protection offered by one dose was similar to that of two doses.
Q2: Against which HPV types did the single dose prove effective?
The trial focused on preventing new, persistent infection with high-risk HPV types 16 and 18, which collectively cause the majority of cervical cancers globally. The single dose of both the bivalent and nonavalent vaccines showed high effectiveness against these two types.
Q3: How does this new data impact HPV vaccination strategy in India?
This data reinforces the recommendation by the NTAGI to introduce the single-dose HPV vaccine into India’s Universal Immunization Program for the primary age group (9–14 years). Consequently, this regimen will significantly improve coverage, reduce costs, and accelerate India’s progress toward cervical cancer elimination.
References
- Kreimer AR et al. Noninferiority of One HPV Vaccine Dose to Two Doses. N Engl J Med. 2025 Dec 03. doi: 10.1056/NEJMoa2506765. PMID: 41337735.
- Man I et al. Evidence-based impact projections of single-dose human papillomavirus vaccination in India: a modelling study. Lancet Oncol. 2022 Dec;23(12):1553-1563.
- WHO. WHO updates recommendations on HPV vaccination schedule. Dec 20, 2022.
- IARC. 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. Nov 12, 2024.
- FOGSI. A Guide Book for Master Trainers: Preventing Cervical Cancer through HPV Vaccination in India. 2024.