Hepatitis C in children

Hepatitis C in children
By Dr Stuart Dorney

This article is from research presented at the Second Australasian Conference on Hepatitis C, Christchurch NZ, 17-19 August 1999.


The world-wide prevalence of hepatitis C among children is between 0 to 0.2%. Children have acquired hepatitis C by vertical transmission [during birth] from their mothers, from intravenous blood products and from injections with unsterile needles. In Australia and New Zealand the most common form of acquisition of HCV by children today is vertical transmission. Prior to blood product screening for hepatitis C, which began in 1990, the most common source of hepatitis C for children was medical blood products. In some countries in the world where needles are used repeatedly to give injections such as immunisations, this is the most common form of acquisition.

Blood acquisition

Donor screening for hepatitis C antibody began in Australia in February 1990. Since then there have only been a few cases of hepatitis C transmission by blood products. In these cases it was due to errors in the blood screening process. Prior to 1990 the children who acquired hepatitis C were in groups who received multiple blood transfusions. These were children with thalassemia or haemophilia [blood disorders], cancer, congenital heart disease and renal [kidney] failure. Prior to 1990 the sero prevalence [prevalence as determined by blood test] of hepatitis C in thalassemic children was 40-60%, in haemodialysis 15%, open heart surgery 5% and cancer 5%.

Vertical transmission

For the future, vertical transmission will be the most common form of transmission in children. Thankfully this is fairly low.

In mothers who are viremic at the time of delivery (ie. they are HCV RNA positive) the incidence of transmission to children is about 5%. If the mother is HIV positive as well as HCV RNA [PCR] positive the risk rises to 35%. No other factors have been shown to give increased risk of hepatitis C to children of hepatitis C positive mothers. In particular breastfeeding has not been shown to be a risk factor. The time of transmission risk appears to be at delivery.

When testing babies of hepatitis C positive mothers for hepatitis C it has to be remembered that babies receive hepatitis C antibody passively via the placenta and thus are antibody positive at birth.

In fact most babies under one year of age who are HCV antibody positive are not infected [PCR positive]. This passive maternal antibody can persist in the baby's serum for up to 18 months. Thus testing babies under this age for hepatitis C can only be reliably done if one tests for HCV RNA.

The current recommendation for testing children of hepatitis C positive mothers is that if the child is well and has normal liver function is to wait until after 18 months of age. However a case can be made for mothers who are known to be HCV RNA positive at the time of delivery to test their children at 2 to 3 months of age but only by HCV RNA. It is not cost effective to test all children.

Infection outcome

What happens to children infected with HCV? The only data available relates to children who acquired HCV from blood transfusion or blood products prior to 1990. Around 60% suffer a chronic infection but the majority are asymptomatic. The serum transaminases [ALT] are normal or only mildly abnormal in most. In a small number of children who have had liver biopsies performed the microscopic changes have been minimal. It is not known how many children will develop cirrhosis. With vertical transmission long term data is still awaited but some children have been documented to lose HCV RNA after 2 to 3 years.

Treatment

Regarding treatment of hepatitis C in children, there is not a lot of data available. In the studies that have been done the numbers have been small and there are few controlled studies. Based on this limited data there is an early response and a sustained response to interferon equivalent to the response seen in adults for transfusion related infection.

There is no data yet of combination therapy of interferon with Ribavirin. There is no data on treating children who acquire hepatitis C via the vertical route. Hepatitis B is not an exact analogy but interferon treatment for vertically acquired hepatitis B does not appear to be effective. What will we see in the future regarding hepatitis C in children? We will be following children who are infected vertically to see what happens to them in the long term. New treatments may become available.

* Stuart Dorney is Head of the Hepatology Unit, New Children's
Hospital, Westmead, Sydney.



This article is from research presented at the Second Australasian Conference on Hepatitis C, Christchurch NZ, 17-19 August 1999.


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