Implementation considerations To be most effective in promoting access, HCV treatment programmes to reach children and adolescents need to be aligned and integrated as much as possible with programmes for adults, with pooled procurement and streamlined supply chain management.

• 1.Inclusion of case-finding, testing, care and treatment of children and adolescents in national plans and guidelines A major constraint to implementation of these recommendations is that, currently, few LMICs have included adolescents and children in their national viral hepatitis strategic plans or their testing and treatment guidelines (4). As a result, most cases in adolescents and children remain undiagnosed and untreated. There remain significant gaps and missed opportunities for diagnosis and documenting the HCV infection status of children of infected mothers or parents. All countries should now include HCV case-finding and testing strategies and treatment (based on the recommendations of the 2017 WHO HCV testing guidelines (14)) for adolescents and children in their national guidelines. This includes focused testing of adolescents from populations most affected by HCV infection (for example, people who inject drugs, men who have sex with men, HIV-infected persons and children of mothers with chronic HCV infection, especially if HIVcoinfected) and those with a clinical suspicion of viral hepatitis.

• 2.Provision of care and treatment by non-specialists Trained non-specialist paediatricians can treat HCVinfected children and adolescents. The few DAAexperienced HCV-infected children and adolescents and those with cirrhosis may be most appropriately managed under the supervision of a paediatric specialist. Training modules (online and in-person) are needed to support task-sharing of care and treatment by non-specialist paediatricians.

• 3.Resource and access considerations Based on market-sizing estimates from the Clinton Health Access Initiative, approximately two thirds of the estimated 3.2 million HCV-infected adolescents and children (those whose weight is generally >25 or 30 kg) can use existing adult doses of the recommended DAA regimens. The remaining estimated 1.05 million HCV-infected children may require specific paediatric dosage and formulations. This includes all children in the 3–5 year age band and 80% of those ages 6–11 years (26). Countries should plan to make DAA regimens available for lower age and weight bands.

• 4.Service delivery for adolescents

• Delivering adolescent-friendly services. Providing services for adolescents requires approaches that are -focussed on and friendly to adolescents. WHO has developed standards for delivering quality services for adolescents (28). Engaging adolescents in testing for both viral hepatitis and HIV, either in health services or in the community, should be based on adolescent-friendly principles to ensure that psychological as well as medical needs are addressed. Services need to be convenient and available, offer flexible opening hours and/or walk-in or same-day appointments
• Vulnerable adolescents. Special considerations are needed for particularly vulnerable adolescents, those who are at higher risk of acquiring infection and have poor access to services. These include those who are homeless, those living on the streets, orphans, boys who have sex with men, those in multiple or concurrent sexual partnerships and those who are sexually exploited or trafficked. Specific campaigns, use of social media or other Web-based approaches, and involving adolescents in identifying appropriate language may help to reach this group in some settings.
• Age of consent. A high legal age of consent to medical care can pose a barrier to adolescents’ access to HIV and viral hepatitis testing. The age of consent for HIV testing varies from country to country. Testing services should be aware of laws and policies governing the age of consent and develop appropriate procedures based on this legal framework to ensure that children and adolescents have access to testing.