HIV-VAC Network: with more than 235 members from > 30 countries, HIV-VAC's objectives are to deliver a mutually supportive network of investigators, communication and advocacy for human infection challenge (HIC) studies through stakeholder engagement, pump-priming projects to enable, enhance and extend HIC, focus on LMIC capacity-building for conducting HIC studies, develop and share topic-specific guidance and best practice including regulatory and ethical frameworks.