Between 23,000 and 46,000 U.S. children live with chronic hepatitis C virus with a prevalence of 0.17% anti–hepatitis C virus (HCV) antibody positivity in those aged 6-11 years and 0.39% among children aged 12-19 years. In the United States, genotype 1 is most frequent, followed by genotypes 2 and 3. About 99% of cases result from vertical transmission; transfusion-related cases have not been observed in recent decades.Only viremic mothers are at risk of transmission as those who have spontaneously cleared HCV viremia or have been treated successfully do not risk transmission. Maternal HCV viral load appears to be a risk factor for HCV transmission, however transmission is reported at all levels of viremia.
In conjunction with the opioid epidemics, the prevalence of HCV infection has increased over the last decade. The Centers for Disease Control and Prevention reported that, between 2009 and 2014, the prevalence of HCV infection increased from 1.8 to 3.4 per 1,000 live births. They identified substantial state-to-state variation with the highest rate in West Virginia (22.6 per 1,000 live births), and the lowest in Hawaii (0.7 per 1,000 live births). The implications are clear that increasing numbers of newborns are exposed to HCV and, if transmission rates are between 1% and 5%, 80-400 U.S. infants each year acquire HCV infection.
HCV in children
HCV in children is almost always associated with persistent transaminitis. Chronic infection is defined as the persistence of HCV RNA for at least 6 months, and clearance of HCV infection is determined by the persistent disappearance of HCV RNA. Regardless of infection status, an infant may have detectable maternal anti-HCV antibody in serum until 18 months of age, resulting from passive transfer. In addition, prolonged infection can lead to cirrhosis, hepatocellular carcinoma, or decompensated liver disease. Potential extrahepatic manifestations including reduced physical and psychosocial health also are linked to chronic HCV. Autoimmune disease also has been reported in children with HCV. As well, the stigma of HCV elicits fear in school and child care settings that is a result of public misunderstanding regarding routes of hepatitis C transmission. No restriction of regular childhood activities is required in the daily life of HCV-infected children.
Taken together, increasing rates of HCV infection in pregnant women, increasing numbers of exposed and infected infants annually, potential for both short- and long-term morbidity, and curative nontoxic treatment,
Screening for HCV
There is considerable discussion about which strategy for screening of at-risk infants is more appropriate. Some groups advocate for HCV-RNA testing within the first year of life. Proponents argue the use of a highly sensitive RNA assay early in life has potential to increase detection of infected infants while a negative result allows the conclusion the infant is not infected. Advocates hypothesize that early identification has potential to improve continued follow-up.
Opponents argue that early testing does not change the need for repeat testing after 18 months to confirm diagnosis. They also argue that HCV RNA is more expensive than an antibody-based testing; and treatment will not begin prior to age 3 as there is still opportunity for viremia to spontaneously clear.
Direct acting agents licensed
Ledipasvir/sofosbuvir (Harvoni) was initially demonstrated as curative for genotype 1, 4, 5, or 6 infection in a phase 2, multicenter, open-label study of 100 adolescents with genotype 1 treated for 12 weeks. Sustained virologic response (SVR) was documented in 98% of participants.The regimen was safe and well tolerated in this population, and the adult dosage formulation resulted in pharmacokinetic characteristics similar to those observed in adults. Two clinical trials supported the efficacy of ledipasvir/sofosbuvir in the pediatric population aged 3-11 years. This regimen also is recommended for interferon-experienced (± ribavirin, with or without an HCV protease inhibitor) children and adolescents aged 3 years or older with genotype 1 or 4. A 12-week course is recommended for patients without cirrhosis; 24 weeks is recommended for those with compensated cirrhosis. The combination of ledipasvir/sofosbuvir is the only treatment option for children aged 3-6 years with genotype 1, 4, 5, or 6 infection.
The efficacy of sofosbuvir/velpatasvir (Epclusa) once daily for 12 weeks was first evaluated in an open-label trial among children aged 6 years and older with genotype 1, 2, 3, 4, or 6 infection, without cirrhosis or with compensated cirrhosis. Subsequently, the “cocktail” was evaluated in children aged 6-12 years, with 76% genotype 1, 3% genotype 2, 15% genotype 3, and 6% genotype 4. SVR12 rates were 93% (50/54) in children with genotype 1, 91% (10/11) in those with genotype 3, and 100% in participants with genotype 2 (2/2) or genotype 4 (4/4). Sofosbuvir/velpatasvir was approved in March 2020 by the Food and Drug Administration for pediatric patients aged 6 years and older. Given its pangenotypic activity, safety, and efficacy, sofosbuvir/velpatasvir is currently recommended as a first choice for HCV treatment in children and adolescents aged at least 6 years.
The daily fixed-dose combination of glecaprevir/pibrentasvir (Mavyret) was approved in April 2019 for adolescents aged 12-17 years, and weighing at least 45 kg.Treatment is for 8 weeks, and includes treatment-naive patients without cirrhosis or those with compensated cirrhosis. SVR12 rates for Mavyret have ranged from 91% to 100 % across clinic trials. FDA approval and HCV guideline treatment recommendations for direct-acting antiviral (DAA)–experienced adolescents are based on clinical trial data from adults. Given its pangenotypic activity, safety, and efficacy record in adult patients, glecaprevir/pibrentasvir is recommended as a first choice for adolescent HCV treatment. Glecaprevir/pibrentasvir once approved for children less than 3 years of age will be safe and efficacious as a pangenotypic treatment option in children with chronic HCV infection.
Tools for identifying HCV infected infants as early as a few months of age are available, yet studies demonstrate that a minority of at-risk children are tested for HCV using either an HCV polymerase chain reaction strategy early in life or an anti-HCV antibody strategy after 18 months of age.
Therapy with direct-acting agents is now licensed to those aged 3 years and offers the potential for cure, eliminating concern for possible progression after prolonged infection. Such therapy offers the potential to eliminate the stigma faced by many children as well as the hepatic and extrahepatic manifestations observed in children. Medication formulation and the child’s abilities to take the medication needs to be considered when prescribing DAAs. It is important to assess if the child can successfully swallow pills. Currently, Harvoni is the only medication that comes in both pellet and pill formulations. The dose is based on weight. The pellets need to be given in a small amount of nonacidic food; they cannot be chewed.
All children with chronic HCV infection are candidates for treatment. When significant fibrosis and/or cirrhosis is present treatment should not be delayed once the child is age 3 years; when only transaminitis is present, treatment can be delayed. In our experience, parents are eager to complete treatment before starting kindergarten.
Liver biopsy for obtaining liver tissue for histopathologic examination is not routinely indicated in children with chronic HCV infection but should be evaluated case by case. Noninvasive tests of hepatic fibrosis have been used in children, these include serologic markers (i.e., FibroSure) and radiologic tests such as ultrasound-based transient elastography (i.e., Fibroscan). Validation for pediatric patients is variable for the different serologic tests. Studies have shown that Fibroscan using the M probe is feasible for a wide range of ages, but poor patient cooperation may make measurement difficult.
Further details regarding dosing and choice of formulation is available at https://www.hcvguidelines.org/unique-populations/children.
Dr. Sabharwal is assistant professor of pediatrics at Boston University and attending physician in pediatric infectious diseases at Boston Medical Center. Ms. Moloney is an instructor in pediatrics at Boston University and a pediatric nurse practitioner in pediatric infectious diseases at Boston Medicine Center. Dr. Pelton is professor of pediatrics and epidemiology at Boston University and public health and senior attending physician at Boston Medical Center. Boston Medical Center received funding from AbbVie for study of Harvoni in Children 3 years of age and older. Email them at [email protected].