Deborah Watson-Jones

Co-Principal Investigator

John Changalucha

Co-Principal Investigator

Kathy Baisley

Co-Principal Investigator

Victoria Ewing

Trial Manager

Adding a Male Single Dose HPV Vaccination to Female HPV Vaccination in Tanzania (Add-Vac study)


Cervical cancer, caused by human papillomavirus (HPV) infection, is a major public health problem. Tanzania bears one of the highest burdens of cervical cancer globally. In 2018, the World Health Organization (WHO) Director General announced his commitment to eliminate cervical cancer. One of the strategies that might reduce the burden is gender-neutral HPV vaccination; offering HPV vaccination to both males and females. Vaccinating males protects them and contributes towards protecting unvaccinated girls and boys against HPV through herd immunity. One potential approach is to offer vaccination to boys with a single dose of HPV vaccine as a catch-up campaign.

The Strategic Advisory Group of Experts (SAGE) conducted a review of new data on single-dose studies (including the DoRIS trial in Mwanza) and in December 2022 the WHO made a recommendation allowing countries to choose between 1 dose or 2 doses for 9–20-year-old females and males. Given the low vaccine uptake through the national programme in girls in Tanzania, our goal is to assess the impact of adding male HPV vaccination with one dose of HPV vaccine, alongside the Tanzanian national HPV vaccination programme.

Primary objective

To measure the impact of adding a single-dose male HPV vaccination strategy to the national HPV vaccination programme in girls.


This is a phase 4 unblinded cluster randomized trial in Mwanza region, northwestern Tanzania. A community-based baseline survey was conducted in 26 rural communities across Mwanza region reaching approximately 12,000 households, where 6,000 men and women aged 18-21 provided a sample for HPV testing. This will be used to establish the baseline prevalence of HPV across all clusters. Communities were then randomized to either the intervention or control arms. In intervention communities, in addition to routine HPV vaccination of girls through the national programme, all boys and men aged 14-18 are offered single-dose HPV vaccination. In control communities, routine HPV vaccination of girls continues as per standard practice. A small cohort of boys and men from one or two clusters will then be recruited to participate in a follow-up study exploring immunological responses to HPV single-dose vaccination in boys for 24 months. A final follow-up survey to measure HPV prevalence will be conducted 36 months after vaccination with 13,000 men and women aged 18-21 years.


London School of Hygiene & Tropical Medicine (LSHTM), UK: Richard Hayes, Hilary Whitworth, Shelley Lees, Mark Jit; MITU, Tanzania/LSHTM, UK: Saidi Kapiga, Jackton Indangasi, Susan Kelly; MITU, Tanzania: Ramadhan Hashim; University of York, UK: Charles Lacey; University of Cambridge, UK: Margaret Stanley; Institut Català d' Oncologia, Spain: Miquel Angel Pavón Rabas; Karolinska Institute, Sweden: Joakim Dillner

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