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Challenges of Hepatitis B infection in Children. Tammy Meyers Jockey Club School of Public Health and Primary Care, Chinese University of Hong Kong a nd Department of Paediatrics and Child Health, University of the Witwatersrand. Hepatitis B Fact sheet N°204 Updated July 2015.
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Challenges of Hepatitis B infection in Children Tammy Meyers Jockey Club School of Public Health and Primary Care, Chinese University of Hong Kong and Department of Paediatricsand Child Health, University of the Witwatersrand
Hepatitis B Fact sheet N°204 Updated July 2015 Improved hepatitis B virus vaccination coverage has decreased the chronic infection rate in children from 8-15% to <1% in many countries
Prevalence of Chronic Hepatitis B infection among adults (2012) Epidaemiology Disease data source: Ott JJ, Vaccine. 2012; 30(12):2212–2219 • ~2 billion people infected with HBV • 240 million with chronic HBV(90 million in China) • 650 000 deaths per year • > half of all liver cancers are associated with HBV • ~5-15% of 34 million PLHIV coinfected with HBV Hepatitis B Fact sheet N°204 Updated July 2015
HBV monoinfection pregnant women • HBV Asian pregnant women • In Hong Kong routine neonatal immunisation since 1988, • anti HBsAgseroprevalance in pregnant women decreased from 11.3% in 1990 to 6.2% in 2014 Surveillance of viral hepatitis in Hong Kong – 2014 Update http://www.info.gov.hk/hepatitis/doc/hepsurv14.pdf • HBV in African pregnant women ranges from 4%-17.1% Healy et al, HIV/HBV coinfection in children and antiviral therapy. Expert Rev Anti Infect Ther. 2013
HBV/HIV Coinfection and maternal-infant transmission • HBV/HIV coinfection ranges from 0.4%-7.1% • KZN – 5.3% prevalence of HBV infection and 3.1% prevalence of HBV/HIV co-infection in stored specimens from 570 PW, (Thumbiran et al SAMJ 2014) • Soweto - HBsAg positivity in 14/189 (7.4%) preg HIV + women and HBV transmitted to 4 infants (Hoffman CJ et al JIAS 2014) Beghin JC et al. J Med Virol. 2016 Jun 13
Transmission • In endemic countries, mother-to child transmission of HBV is the predominant route of transmission • Horizontal transmission from an infected child to an uninfected child during the first 5 years of life • Traditionally thought to be more common in Africa • Breastfeeding not a risk for transmission • close contact with mother associated with post-partum transmission
~ 20-30% of chronically infected will develop complications such as cirrhosis and hepatocellular carcinoma http://virology-online.com/viruses/HepatitisB.htm
Hepatitis B virus • DNA virus from the Hepadnaviridae family • Enveloped and encapsulated • Important proteins include • An surface protein called surface antigen – HBsAg • A structural nucleocapsid core protein – HBcAg • A soluble nucleocapsid protein – HBeAg http://medlibes.com/entry/hepatitis-b
Natural History of Chronic Hepatitis B infection in children Immune Immune Immune Immune clearance control escape tolerance HBeAg+ve HBeAg–ve > < < > HBV-DNA ALT HBeAg +ve chronic hepatitis HBeAg –ve active chronic hepatitis Inactive (carrier) state*
Natural History with HIV/HBV coinfection • Ivory Coast- 34 children followed for 30 months • development of anti-HBeAg did not result in control of viral replication • children with more active HIV disease have less immune control of HBV • Romania- cohort of coinfected adolescents, 1 year follow-up • 126/161 (78%) had evidence of HBV infection - anti-HB core Ab • 43% HBsAg positive, 25% HBeAg positive • Adolescents with more severe immune suppression had higher levels of HBV DNA and were more likely to be HBsAg positive • After 1 year, 31% seroconverted to anti-HBe with the clearance rate significantly less in those with severe immune suppression Healy et al, HIV/HBV coinfection in children and antiviral therapy. Expert Rev Anti Infect Ther. 2013
Natural History with HIV/HBV coinfection Liver-related mortality rate (per 1,000 person-years) Multicenter prospective cohort study of 5293 men who had sex with men (USA) Thio CL, et al. Lancet 2002;360:1921-6 (1) Perillo RP, Regenstein FG, et al. Chronic hepatitis B in asymptomatic homosexual men with antibody to the human immunodeficiency virus. Ann Intern Med 1986:105:382-3 Extrapolating from HIV/HBV-coinfected adults: • Lower rates of clearance of HBeAg • Increased serum HBV DNA viral load1 • Reactivation of hepatitis in asymptomatic carriers • Increased liver injury • More rapid onset fibrosis, cirrhosis and HCC • Higher mortality and morbidity
WHY are children and adolescents still infected with HBV? • Many countries not yet instituted routine screening of pregnant women and HBIG to babies • Birth vaccine dose not implemented averywhere • Residual infection transmitted at a rate 5-15% in HBsAg + women • Women with high HBV DNA levels may transmit HBV to their neonates despite vaccination • Marginalised populations (higher risk) may be missed • Some children fail to respond to vaccine • HIV-exposed less likely to be immunised • HIV-infected children have a less robust initial response to HBV vaccine (Healy et al, HIV/HBV coinfection in children and antiviral therapy. Expert Rev Anti Infect Ther. 2013) In China alone, with <1% transmission rate, an estimated 50 000 children per year still become infected at birth Haruki Komatsu, Journal of Gastroenterology, 2014
Clinical Manifestations in children • Children are typically in the immune tolerant phase (usually asymptomatic) • Cirrhosis and hepatocellular carcinoma are infrequent in children and adolescent estimated annual incidence of cirrhosis of 2-3% • Unclear which cases will progress to cirrhosis
Clinical Manifestations • Gianotti-Crosti syndrome Fulminant hepatitis in a newborn (more common in women HBsAg + but HbeAg –ve) Membranous or mebranoproliferative nephropathy – nephrotic syndrome Polyarteritisnodosa
Monitoring serology in children • CDC now recommends PVST from 9-12 months, (1-2 months after vaccination course completed) • PVST can identify early those who have not responded to vaccine, and require revaccination • Identify those infants who have been infected • PVST not commonly performed in low resource settings
Duration of immunity post vaccination • Many studies confirm the long term immunity afforded by Hep B vaccination • 20 years after vaccination • Despite waning titres, most have an anamnestic response after 1 booster dose (Bagheri-Jamebozorgi M, Human Vacc Immunotherapy 2014) • Evidence of HBsAg specific cell-mediated immunity in up to 80% (Saffer H Hepat Mon 2014) • No recommendation for routine booster dose
Immune Response to vaccination in KZN • In SA concerns that immune response to Hep B vaccine may be suboptimal in children • 210 paed oncology patients included (median age 6.5 years), 84 (40%) had no immunity to hepatitis B despite presumed vaccination • Six patients had anti-HBc positivity, consistent with previous infection • No patients had active hepatitis B infection (hepatitis B surface antigen-positive) • Most HIV-infected patients were not immune to HBV (80.0%). (Büchner A et al SAMJ 2014;104 Beghin JC et al. J Med Virol. 2016 Jun 13
Booster Vaccination The following should be monitored and receive booster dose if anti-HBs antibodies <10mIU/mL • Health care providers including laboratory staff • HIV-infected patients • Haemodialysis patients • Immunocompromised patients • MSM or multiple sexual partners • Chronic hepatitis/liver disease (non - HBV) • Injection drug users • Inmates/staff; staff for mentally disabled
Evaluation of Children with HBV • Clinical evaluation routine for all with CHB • Liver function tests, PTT, FBC and platelets • Non-invasive tests may reduce need for liver biopsy WHO
Therapeutic Endpoints Improvedsurvival Anti-HBs+ Improvedhistology Loss of HBsAg Anti-HBe+ Loss of HBeAg Loss of HBV DNA = HBeAgseroconversion TIME With current drugs available cure is not possible
Antivirals active against HBV in order of potency and barrier to resistance WHO Tenofovir recommended for children ≥12 years Entecavir approved for 2-11
Investigations WHO
Treatment for HIV/HBV coinfected adults, adolescents and children WHO Consolidated guidelines on the use of antiretroviral drugs for treating and preventing HIV infection Recommendations for a public health approach - Second edition) • Treat all with ART • Severe chronic liver disease prioritised if necessary • CHB + cirrhosis regardless of ALT levels, HBeAg status or HBV DNA • NRTI drugs for ART – TDF with 3TC or FTC – are active against HBV (including children ≥ 3years) • Treatment of HIV/HBV coinfectionwithout TDF flares of hepatitis B due to IRIS • Treatment discontinuation, especially 3TC, associated with HBV reactivation, ALT flares and, rarely, hepatic decompensation • TDF + 3TC or FTC should be continued when ARV’s regimen changed WHO Guidelines for the prevention, care and treatment of persons with Chronic hepatitis B infection • HBV/HIV coinfected adults, adolescents and children ≥ 3years – TDF + 3TC/FTC + EFV FDC preferred option (Strong recommendation, moderate quality of evidence
Specific issues in paediatric treatment of CHB • Generally children in the immune tolerant phase do not require treatment • Children with ALT values >10 times the ULN may be in the process of spontaneous HBeAgseroconversion and should be observed for several months before treatment is begun • Children with HIV or undergoing immune therapy should be considered for antiviral therapy • Children should be included in clinical trials for newer drugs such as tenofoviralafenamide (TAF) and agents which are being investigated for cure
Summary and recommendations • Paediatric HBV infection has declined dramatically following increased HBV vaccination • Ending HBV transmission to babies is a real possibility: • Routine screening for high risk pregnant women and HBIG • Birth dose should be implemented globally • Increased awareness of risk of HBV/HIV coinfection in children in high burden regions • PVST for infants 1-2 months after last vaccine can identify sero-response to vaccine and identify infected children
Summary and recommendations • Identification and follow up of CHB infected children and adolescents into adulthood is necessary to ensure timeous treatment if indicated • Cohort studies to determine the natural progression of CHB in children and adolescents in the era of routine HBV vaccination • Coinfected HIV/HBV infected children are more vulnerable • need booster vaccination • more intense follow up as CHB disease severity may be worse • Paediatric clinical trials should be expedited investigating improved strategies to prevent transmission, treat and/or cure CHB • Discrimination of people living with chronic hepatitis B infection must end