Hi, this is Tom, and in this episode I'm going to be going through hepatitis B in children.

And you can find notes at 0.0.5.com and in the 0 to Finals Pediatrics book. And you can find

flashcards and questions at members.0.0 tofin.0.com. So let's jump straight in.

Hepatitis B is a DNA virus. It's transmitted by direct contact with blood or bodily fluids

from an infected person. Hepatitis B can be passed from mother to child around delivery, and this is called

vertical transmission. It can also be passed through sharing household products contaminated with

blood, such as toothbrushes, contact between minor cuts or abrasions, and other high-risk

activities such as sexual intercourse or sharing needles.

It's not spread by casual contact, such as ordinary hugging, kissing, provided there's no

mouth sores or bleeding gums, sharing food or coughing.

Most older children and adolescents clear acute infection within several months. However,

a portion develop chronic hepatitis B infection. In chronic infection, the virus persists in the liver

cells with ongoing viral replication and production of viral proteins.

The risk of developing chronic hepatitis B after exposure is around 90% for neonates,

around 30% for young children, and around 10% for older children and adolescents.

Most children with chronic hepatitis B are asymptomatic, with normal growth in development and normal liver function tests.

A small minority will develop cirrhosis or hepatoc cellular carcinoma during childhood.

The risks of these complications increase once they enter adulthood.

Vaccination involves injecting the hepatitis B surface antigen.

In the current UK schedule, children receive the hepatitis B vaccine as part of the six in one vaccine at ages

8, 12 and 16 weeks, with a fourth dose at 18 months for children born on or after the 1st of July

24. Let's talk about the viral markers. Antibodies are produced by the immune system against

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