Leveraging Single-Dose HPV Vaccination to Accelerate Cervical Cancer Elimination: Acceptability, Cost-Effectiveness, and Policy Considerations for Single-Dose Adoption in East Africa

Abstract

Every two minutes, a woman dies of cervical cancer, a disease that is highly preventable. Human papillomavirus (HPV) vaccines protect against high-risk HPV infections, which cause cervical cancer, but only 15% of eligible girls have been vaccinated globally. HPV vaccination uptake remains particularly low in low- and middle-income countries (LMICs) where most cervical cancer-related deaths occur. In 2020, the World Health Assembly (WHA) adopted a global strategy to eliminate cervical cancer that focused on three pillars to be achieved by 2030. These targets include having 90% of girls fully vaccinated with the HPV vaccine by age 15. Recent evidence on the efficacy and effectiveness of a single-dose HPV vaccination led the World Health Organization (WHO) to recommend countries to consider a single-dose HPV vaccination schedule to improve coverage and catalyze progress towards achieving cervical cancer elimination. This dissertation sought to comprehensively assess implementation outcomes of single-dose HPV vaccination, focusing on acceptability, cost-effectiveness of single-dose HPV vaccination in Kenya, and policy considerations for single-dose HPV vaccination adoption in East Africa.Using a mixed-methods study approach, we assessed the acceptability of a single-dose HPV vaccination schedule among healthcare providers (HCPs) in Kenya. We found that most HCPs thought that a single-dose schedule was acceptable, and the lack of information among HCPs was the main reason for disapproval. Additionally, HCPs based at rural facilities had higher acceptability likelihood compared to those based at urban facilities. In chapter 3, we conducted a cost-effectiveness analysis to assess the potential health and economic impact of a single-dose HPV vaccination schedule in Kenya. We found that a two-dose HPV vaccination strategy at 90% coverage had a higher incremental cost-effectiveness ratio (ICER) compared to a one-dose strategy at the same coverage level (US$ $6,508.08/ DALY averted vs US$ $ 197.44/ DALY averted). Additionally, switching to a single-dose schedule would result in US$ $21.4 million in savings over five years, which could fund 2.75 million additional HPV vaccinations. This re-investment could fund catch-up vaccinations, and the greatest DALYs would be averted by supplementing a single-dose strategy with a 90% coverage with a catch-up vaccination for 11- 24-year-old girls (ICER: US$ $ 78.73 / DALY averted). Finally, in chapter 4, we leveraged a rapid review to conduct a framework policy analysis on single-dose HPV vaccination adoption in three East African countries. We found that in Ethiopia, Uganda, and Tanzania, political will was crucial to prioritizing the revision of HPV vaccination policy, and National Immunization Technical Advisory Groups (NITAGs) were central to the single-dose decision-making process. Additionally, across the three countries, the WHO endorsement and availability of key evidence on the burden of the disease, health, and economic benefits of a single-dose schedule played an important role in the policy revision process. In conclusion, single-dose HPV vaccination has the potential to accelerate progress in cervical cancer elimination. Considering its acceptability even among HCPs in rural areas, potential health and economic benefits, a single-dose schedule could simplify logistics and inform policy revisions to improve coverage in Kenya and comparable settings. These findings also have the potential to inform future immunization policy revision initiatives.