ID - Hepatitis B

Question 1

What type of virus is Hep B?

Answer 1

DNA virus

Question 2

How is Hep B transmitted?

Answer 2

Blood or bodily fluids
- Sex
- Needle sharing e.g. IVDU or tattoos
- Contaminated toothbrushes
- Contact with minor cuts or abrasions
- Vertical transmission

Question 3

How long does it take for most children to recover from infection?

Answer 3

2 months

Some can go on to become chronic carriers

Question 4

What happens in chronic hepatitis?

Answer 4

Viral DNA integrated into person’s own DNA

Question 5

What is the risk of chronic hepatitis B development post exposure?

Answer 5

90% neonates
30% children under 5
< 10% adolescents

Question 6

How does chronic hepatitis B affect kids?

Answer 6

Mostly asymptomatic
- Normal growth and development
- Normal LFTs
- Less than 5% develop liver cirrhosis
- Less than 0.05% develop hepatocellular carcinoma before adulthood , risks increase once in adulthood

Question 7

What do different antigens and antibodies indicate?

Answer 7

HBsAg - active infection
HBeAg - viral replication, high infectivity
HBcAb - past or current infection
HBsAb - vaccination, past or current infection
HBV DNA - direct count of viral load

Question 8

How is hep B screened for?

Answer 8

Test for HBcAb and HBsAg, if positive
Further testing for HBeAg and viral load (HBV DNA)

Question 9

What versions of HBcAb are measured?

Answer 9

IgM and IgG versions

IgM
- Active infection
- High titre in acute infection
- Low titre chronic infection

IgG
- Past infection where HBsAg is negative

Question 10

What does HbeAg indicate?

Answer 10

Acute phase of the infection where virus is actively replicating

HBeAg correlates with infectivity

If HBeAg is negative but HBeAb is positive, indicates virus has stopped replicating and now less infectious

Question 11

Which children should be tested for hepatitis B?

Answer 11

• Hep B positive mums
• Migrants from endemic areas
• Close contacts

Question 12

When should children of hep B positive mums be tested?

Answer 12

Screened at 12 months or any time after that

Question 13

To reduce risk of contracting hep B at birth what should be done?

Answer 13

If mother is postiive

Neonate should be given
Hepatitis B vaccine
Hepatitis B immunoglobulin infusion

Both within 24 hours

Question 14

In infants with hep B positive mums when should hep B vaccinations be given?

Answer 14

1 month
12 months

Then follow normal vaccination schedule

Will be checked for HBsAg at 1 year to check if they have contracted hep B

Question 15

Is it safe for hep B positive mothers to breastfeed?

Answer 15

Yes, provided babies properly vaccinated

Babies already exposed to virus during pregnancy and birth

Should receive hep B vaccine and immunoglobulin infusion

Question 16

What type of vaccine is the hep B vaccine?

Answer 16

Surface antigen only

3 doses required at different intervals

Question 17

How is chronic hep B managed?

Answer 17

Most children asymptomatic and do not need treatment

Need regular specialist follow up to monitor
- Serum ALT
- HBeAg
- HBV DNA
- Physical examiantion
- Liver USS

Question 18

If there is evidence of hepatitis or cirrhosis in hep B positive kids what should be done?

Answer 18

Antiviral treatment