Project Summary/Abstract Human papillomavirus (HPV) vaccination is a critical cancer control intervention, particularly in resource- constrained health systems with limited access to screening and treatment services. Malawi, like many African countries, has introduced a national HPV vaccine program targeting preadolescent girls – but coverage remains very low. Clinician recommendation of HPV vaccination is a highly effective evidence-based intervention for increasing uptake of the vaccine, but there is little information on how to encourage clinicians in low- and middle- income countries to deliver this recommendation. The Kupewa project (“prevent” in Chichewa) aims to (A) identify the optimal implementation strategies for increasing clinician recommendation of HPV vaccination for girls and young women aged 9-24 who are living with HIV in Malawi; (B) refine this set of optimized strategies by including information about the strategies’ implementability; and (C) ultimately identify the set of strategies that are effective, implementable, and show sustained effects 18 months after the intervention ends. The study is informed by the Theoretical Domains Framework and the World Health Organization’s Behavioural and Social Drivers (BeSD) of vaccination framework. To our knowledge, this would be among the first applications of intervention optimization alongside implementation science, and among the first to be conducted in a low-income country. The project will leverage a robust research partnership between institutions and highly-qualified investigators in Malawi and the U.S., with engagement of partners from the Malawi Ministry of Health in all phases, from conceptualization to study execution and results interpretation and dissemination. Clinician-facing implementation strategies to promote vaccination recommendation in low- and middle-income countries are understudied but urgently needed to accelerate HPV vaccination programs globally. This study will provide much-needed insight into ways to promote clinician recommendation of HPV vaccination to the highest- risk girls and young women in the country with the second-highest burden of cervical cancer globally.