Diagnosis and vaccination Dr Geethani Galagoda Consultant Virologist Medical Research Institute Symposium on Hepatitis Prevention Hepatitis Day 2015
Diagnosis and vaccination
Dr Geethani Galagoda
Consultant Virologist
Medical Research Institute
Symposium on Hepatitis Prevention
Hepatitis Day 2015
Points at which laboratory can contribute
• Screening for infection
• Diagnosis of infection
• Staging of disease severity
• Decision on treatment ▫ Before
▫ During
▫ After
Markers of hepatitis B
• Samples: serum or plasma • Antigens
▫ Hepatitis B surface Antigen ▫ Hepatitis B e antigen ▫ Hepatitis B core antigen – not seen in blood
• Antibody ▫ Hepatitis B surface antibody ▫ Hepatitis B e antibody ▫ Hepatitis B core antibody (IgM and total)
Hepatitis B surface Antigen (HBsAg)
• First serological marker – 3-5 weeks (30 d) after
exposure, before hepatic injury
• Acute infection – cleared in 6 months
• Chronic infection – if persists after 6 months
• Transient positivity seen for 18 days after vaccination
Hepatitis B e Antigen (HBeAg)
• Related to core antigen (soluble nucleo-capsid antigen)
• Indicates active viral replication (HBV DNA > 100,000 –
1 million IU/ml)
• Highly infectious
• Greater risk of progression to liver disease
• Mutant forms do not have HBeAg
• Management depends on the presence of
HBeAg
Hepatitis B core Antibody (HBcAb)
• First antibody to appear, before liver injury • Does not neutralise virus • IgM – recent infection, reactivation of chronic hepatitis • IgG – persists for life
▫ With HBsAb – recovery from natural infection ▫ Alone
Window period False positive Immune with low levels of HBsAb Chronic infection with low levels of HBsAg Reactivation
Hepatitis B e Antibody (HBeAb)
• Appears with clearing of HBeAg
• After a few weeks
• Shows low infectivity
• Good prognosis to disease
Hepatitis B surface Antibody (HBsAb)
• Last antibody to appear
• Alone – after vaccination (protective level ≥ 10 IU/L)
• Indicates immunity to infection with Hepatitis B
• With HBcAb (total) – after recovery from natural
infection
Molecular assays
• Hepatitis B DNA
▫ Qualitative
▫ Quantitative
• Methods
▫ Conventional and Real Time PCR assay
Diagnosis of acute hepatitis B
• Initial testing - HBsAg
• Followed by HB core IgM antibody and HBeAg
• If HBeAg negative – HBeAb
Follow up assay
• Acute infection – repeat HBsAg 6 months after
• To exclude chronic infection
• Persistence of HBsAg after 6 months – chronic
infection
• Chronic infection – HBeAg followed by HBeAb
• DNA viral load assay
DNA viral load assay
• Correlates with circulating viral particles
• Either measured as copies / ml or IU / ml
• Detection limit should be 15 IU / ml
• Treatment recommended if HBV DNA - > 20,000 IU / ml
Follow up
• Patients not on treatment
▫ HBsAg, HBeAg, ALT levels and DNA viral load assay annually
• Patients on treatment
▫ HBsAg, HBeAg, DNA viral load assay every 3 months
• Discontinuation of treatment
▫ HBsAg, HBeAg, DNA viral load assay every 3 months for the
first year
Guidelines for the prevention, care and treatment of patients with chronic hepatitis B infection WHO March 2015
Diagnosis of HCV
• HCV antibody (positive 1-6 months after
infection)
• All anti-HCV positive patients
▫ HCV RNA for confirmation
▫ Viral load assay
▫ Genotyping
Treatment of HCV
• HCV RNA testing at initiation of treatment
• Dual therapy ▫ Baseline, 4, 12, 24 weeks, end of treatment, 12 and 24
weeks after therapy
• Follow up ▫ Annual or more frequent HCV RNA assays for patients
with SVR
EASL Clinical guidelines: Management of hepatitis C virus infection 2014
Hepatitis B - Populations at risk
• Health care workers
• Patients
▫ Multi transfused patients / Chronic haemodialysis / Treatment for
malignancy
• People with high risk sexual behaviour
▫ Commercial sex workers / MSM
• Intravenous drug users
• Inmates of mental health / long term care institutions
• Prisoners
• Family contacts of carriers
• Armed forces / Police
Prophylaxis - (specific prevention)
Vaccine - long term protection
plasma derived / recombinant comparable efficacy & safety
HBIG - short term protection
NBTS 24/05/07
Hepatitis B immunoglobulin
• Human plasma with high titer of Hep B antibody
• Given with hepatitis B vaccine
• Not for treatment of hepatitis B
• Given within 48 hours, (up to a week), Depending on body
weight
• Different site from vaccine – antero-lateral thigh
• Do not give intra-venously
NBTS 24/05/07
Hepatitis B immunoglobulin cntd.
• Indications
▫ Parenteral exposure, before starting vaccination
▫ Neonates whose mothers are HBeAg positive
▫ Known non-responders
• CI - bleeding disorder
• Pregnancy?
• SE – very rare
Pre Exposure Prophylaxis
• Given before exposure to high risk groups
• Pre vaccination screening is not essential
• 3 doses at 0, 1, 6 months
• Check for Anti HBs 1 – 2 months after the 3rd dose
• Routine booster doses & regular testing not recommended
• Transient HBsAg positivity after vaccination
• CI – anaphylaxis to a component
• Safe in pregnancy & breast feeding
• Adverse effects
▫ fever, rash, malaise
▫ GBS
• Response - >100 mIU / ml preferable
▫ >= 10 mIU / ml accepted as adequate
▫ <10 mIU / ml - susceptible
Pre Exposure Prophylaxis contd.
Anti HBs positive - responder (>=10 mIU/ml) Anti HBs negative check for HBsAg
HBsAg positive Carrier - counsel
HBsAg negative Repeat 3 doses of vaccine (1 month apart) Check for Anti HBs
Pre Exposure Prophylaxis contd.
Following two courses of vaccine
Anti HBs positive - responder (45 – 100%)
Anti HBs negative - primary non-responder
• Precautions to avoid exposure • HBIG foll. known exposure to HBsAg + source
NBTS 24/05/07
Primary non-responder
• 10 – 15% do not respond
▫ Over age 40
▫ Obesity
▫ Smoking
▫ Alcoholics
▫ Advanced liver disease
Post Exposure Prophylaxis
• Given within 48 hours, (up to a week)
• Following known / possible exposure
• Vaccine with or without HBIG used
• Depending on
▫ Vaccination & antibody status of the recipient
▫ HBsAg status of the source
• Needs specific advice
Neonatal transmission - prevention
In all other situations -
• HBIG
▫ Within 12 hours after birth, 0.5 ml IM
• Followed by vaccination – 3 doses
▫ Birth – within 12 hours after birth, 1 month, 6 months
▫ With EPI in Sri Lanka - at birth, 1, 2 and 12 months
Management depends on maternal HBsAg and HBeAg status
If mother is HBeAg negative and HBeAb positive •Hepatitis B vaccine - within 12 hours after birth, 1 month, 6 months
Vaccination policy in Sri Lanka
• Childhood vaccination at 2,4,6 months – WHO
recommendation – Birth dose with 2 or 3 follow up doses
• Vaccination of health care workers
• Vaccination of other high risk groups
▫ Multi-transfused patients
▫ Patients undergoing chemotherapy
▫ Patients undergoing haemodialysis
▫ Household contacts of carriers