HPV vaccination program in Panama promises major public health benefits

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At the IDWeek 2024 conference, a study from Panama has shed light on the potential public health impact of transitioning from a 4-valent (4vHPV) to a 9-valent human papillomavirus (9vHPV) vaccination program. The study highlights how expanding the national vaccination strategy to include 5 additional HPV genotypes could substantially reduce the incidence of HPV-related cancers and diseases over the next century.

Background

Panama first introduced the HPV vaccination into its National Immunization Program in 2008, targeting 10-year-old girls. By 2016, the program had expanded to include boys, implementing a gender-neutral quadrivalent HPV vaccination (GNV) to cover both sexes. This move marked significant progress in HPV prevention, but health officials now see even greater potential in the switch to a nonavalent (9-valent) vaccine, according to the authors. The nonavalent vaccine offers protection against five additional HPV genotypes—31, 33, 45, 52, and 58—known to contribute to several cancers.

Objective

The study aimed to quantify the benefits of transitioning from a 4vHPV GNV to a 9vHPV GNV in 10-year-olds across Panama, focusing on the impact this change could have on the reduction of HPV-related diseases and cancers over the next century.

Methods

The researchers employed a dynamic model calibrated specifically for HPV transmission and disease progression in Panama. The model, which assumed lifetime immunity after a two-dose vaccination schedule, examined the effects of sustained vaccination coverage (85% for girls and 80% for boys) over a 100-year period. Outcomes included reductions in HPV-related disease incidences, such as cervical, anal, penile, and head and neck cancers, as well as cervical intraepithelial neoplasia (CIN) grades 1 and 2/3. Local Panamanian data was used where available, with external data serving as proxies when necessary.

Results

The study predicts that, compared to the current 4-valent program, the 9-valent vaccination program will yield faster and more pronounced reductions in the incidence and mortality of HPV-related diseases. The most significant impact will be observed in the prevention of cervical cancer and its precursors:

• Cervical cancer incidence is projected to decrease by an additional 16.5%.
• CIN2/3 cases (high-grade cervical lesions) could drop by 30%.
• CIN1 cases (low-grade cervical lesions) are expected to fall by 43.8%.

The study also anticipates reductions in other cancers related to HPV, including anal, penile, and head and neck cancers, for both genders:

• Anal cancer incidence in females is projected to decrease by 7%, and by 4.5% in males.
• Penile cancer incidence could drop by 7.7%, while head and neck cancer cases might see a 3.5% reduction in females and 1.4% in males.

In total, the 9vHPV GNV program is expected to prevent approximately 3,231 cases of cancer and avert 1,798 deaths over the 100-year horizon, with the majority of these cases being cervical cancer.

Limitations

While the findings are promising, the study’s projections depend on sustained high vaccination coverage rates over the long term, which may be challenging. Additionally, the model does not account for potential advances in cervical cancer screening methods, which could influence future disease outcomes.

Conclusion

The transition to a 9-valent HPV vaccination program in Panama holds the promise of significant public health gains, especially in reducing the burden of cervical cancer. The addition of 5 more HPV genotypes in the vaccine regimen will offer broader protection, benefiting both males and females and further advancing the country’s efforts to curb HPV-related diseases. These findings underscore the importance of considering a switch to 9vHPV in national vaccination strategies, with Panama potentially leading the way for other countries in the region.

This study serves as a call to action for policymakers, health care providers, and public health officials to invest in broader vaccine coverage and HPV prevention measures, ensuring long-term benefits for future generations.

This article was originally published by our sister publication Contemporary Pediatrics.

Reference:

Orengo JC, Rendon AM, Lima BC, et al. Assessing the Public Health Impact of Transitioning from a 4-valent to a 9-valent Human Papillomavirus Vaccination Program in Panama. Poster. Presented at: IDWeek 2024. October 16-19, 2024. Los Angeles, California.