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)

HBV DNA – 10-20 d after exposure

HBsAg 30 d after exposure

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 vaccination

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

Thank you