Cervical cancer is the fourth most common cancer in women around the world, and nearly all cases are due to human papillomavirus (HPV) infection. While there are several vaccines available to prevent HPV, less than 15% of women are fully vaccinated and coverage is even lower in low- and middle-income countries (LMICs).

Including HPV vaccines into national programs in LMICs has been a challenge due to the high cost of the vaccines as well as other logistical and socio-cultural considerations. For instance, the current WHO guidelines call for two doses of vaccine for girls 9-14 years old, and three doses for those over 15—a vaccination schedule that can be costly and difficult to maintain.

To help increase HPV vaccination coverage in LMICs, IVI is conducting a study to demonstrate the effectiveness of a single dose of HPV vaccine. Dr. Julia Lynch, the Principal Investigator of the study, explains, “a simplified schedule would help facilitate new options for current national immunization programs and lower their costs. And for countries that have not yet introduced HPV vaccine into their programs, a single-dose regimen may be an achievable—and urgently needed—option.”

A community impact study in Thailand

In late 2018 to early 2019, IVI provided more than 8,000 8th grade girls in the Udon Thani and Buri Ram provinces of Thailand with either one dose of Cervarix® HPV vaccine or the currently recommended two doses in a school-based vaccination campaign.

In 2020, our Year 2 Survey showed that both a single dose and two doses of HPV vaccine significantly decreased the prevalence of HPV. The results of this survey were part of a global data package that provided substantial evidence to support the benefits of a single-dose HPV regimen which was then submitted to the WHO Strategic Advisory Group of Experts on Immunization (SAGE).

After reviewing the evidence, the SAGE concluded that a single dose delivers solid protection against HPV and recommended updating the current dose schedules. In the update, SAGE recommends a one- or two-dose schedule for girls and young women 9-20 years old.

This fall, the same Thai girls from Udon Thani and Buri Ram are going into Grade 12, and IVI is preparing to conduct the Year 4 Survey to determine long-term vaccine effectiveness as well as to compare the effectiveness of the two vaccination schedules.

Ahead of the survey, IVI’s clinical development team led a “training for trainers” to better equip the Thai Ministry of Public Health coordinators who will ultimately train the study site staff. The training covered the protocol overview, a refresher on Good Clinical Practice, field sampling, how to complete study eligibility checks, urine and blood sample collection and packing methods, data collection, and more.

“The results of this single-dose impact study have already led to considerable advances in the international effort to increase HPV vaccine coverage,” says Dr. Lynch. “Additionally, for most clinical development projects at IVI, a significant aspect of our scientific collaborations is to build capacity with and among our partners. We’re grateful to the Thai MOPH for their continuous partnership and hope this Year 4 Training will benefit them and their local site coordinators well beyond our joint study.”

by Aerie Em

Last updated September 29, 2022