Hep B/C + BBVs - 29-31 Flashcards
Describe the global epidemiology of HBV
Around 550 m people chronically infected w/ viral hepatitis worldwide
China, India, SSA + Amazonian basin has high Hep B prevalence - increased risk of perinatal infection in Asia
What is the mode of transmission for HBV?
Vertical - mother to baby; blood to blood
Horizontal - children/siblings
Sexual transmission
What are the risk factors for HepB?
MTCT - 90% chronicity
IVDU
Sex workers
Unsafe medical practices
What is the relationship between risk of developing chronic infection and age?
Inversely related Higher risk at younger age Perinatally 90% Childhood 30-50% Adult 5%
What are the interventions available for prevention of HBV?
Safe + 95% effective vaccine
1st dose at 4 weeks but this is too late to prevent perinatal transmission - should ideally be given straight away
3rd dose coverage is poor
If vaccination maintained, 1.3m deaths averted by 2030
Give a case study of a successful national HBV vaccination programme
Taiwan 1984
Earliest nationwide HepB mass vaccination
Good strategy, good uptake of vacc + good antenatal programme - NOT representative of all countries
Prevalence of HBV in younger age groups reduced to < 1%
Why won’t vaccination address HBV worldwide?
Immunisation coverage is suboptimal
Infant vaccination doesn’t eliminate risk of perinatal transmission
Large pool of chronically infected carriers still remains for decades
What % of blood supply in Africa is screened for HBsAg?
< 50% (WHO)
What treatment is available for HBV?
Interferon
Nucleos(t)ide analogue drugs e.g. tenofovir (also Tx for HIV) + entecavir (high potency + high barrier to resistance) BUT cost + access still remains an issue
Tx reduces risk of progression to cirrhosis + HCC
AIM IS VIRAL SUPPRESSION - persistence of viral cccDNA in host cells (HBV) whereas in HIV there is latency in CD4 memory cells
How does treatment for HBV differ from HCV?
HBV= Long term viral suppression like HIV HCV = Sustained virological response as HCV has entirely cytoplasmic lifecycle; < 1% relapse - CURE like TB
Why isn’t hepatitis treated in resource poor settings?
Not on global health agenda - lack of political will
Complex diagnostics - needs to be accessible + simplified
Drug cost + availability - global fund can get generic prices for some drugs incl tenofovir but only for HIV Tx or if co-infection w/ HIV/HBV
Skills + education - management + screening
What can be done to improve hepatitis treatment that is related to HIV treatment?
Integrate with HIV services - there is an obvious overlap and infrastructure is already in place for HIVW
Benefits: trained staff; lab facilities; drug supply (tenofovir); management of co-infection
Problem: potential for stigmatisation
What study shows the cost-effectiveness of Tenofovir?
PROLIFICA study in Gambia, Howell et al., 2016
Also showed that barriers still exist
What needs to be done in the future to improve health outcomes for hepatitis?
R&D to improve data collection Strengthen laboratory capacity Build clinical capacity Build clinical expertise Integration w/ HIV services Drug pricing Education
What is the epidemiology of HCV?
Viral hepatitis is 7th leading cause of death - most in India, China + SE Asia
Approx 170 m infected - high prevalence in UK, USA + Central Europe
Is there a vaccine for HCV?
NO - only one out of all the types of hepatitis w/o vaccine
Why is there no vaccine for HCV?
Technically difficult to develop attenuated vaccine and not enough funding
What are the factors contributing to ongoing transmission? (x4)
Unsafe medical practices e.g. transfusion, medical care
IVDU
Sexual transmission
MTCT
What are the prevention methods for HCV? (X3)
Screening of blood products for BBV
Provision of disposable medical needles
Needle exchange + OST Tx for those IDU
What are the Tx options for HCV?
Pegylated interferon - directly hinders replication of virus
Ribavirin - inhibits viral growth
Direct Acting Antiviral (DAA) - 95% Cure rate
What are the barriers to HCV treatment? (x3)
3 C’s
Costs
Cure rates - Hep C most likely to become chronic + outcomes in HIC v similar to LIC
Complexity
What study shows the length of time to achieve SVR for Hep C?
Ford et al.
Showed 12 weeks of treatment needed to achieve SVR + therefore < 1% relapse
Name and describe a Global Strategy to tackle viral hepatitis
Global Viral Hepatitis Strategy 2016-21
Approved by WHA 2016
Elimination of viral hepatitis as a public health threat
80% eligible patients treated for HBV + HCV by 2030
Task shifting + simplification
Scale up diagnosis + Tx
What are the barriers to viral hepatitis treatment?
Research + surveillance Simplification Cost of care Patient + community engagement Access to services Task shifting Integration with other services e.g. HIV Human rights Political will + financing
