CURRENT PERSPECTIVES IN HEPATITIS ¨C C
Mathur YC
Aditya Children¡¯s Hospital, Hyderabad ¨C 500 004.
A.P. India
Hepatitis C is a major health problem worldwide.
Hepatitis C infects nearly 170 million people in the world. HCV prevalence
ranges from 0.1 to 5% in different countries. The incidence in India ranges
from 0.1 to 2.5%. 25% sero positivity was found in multitransfused
thalassaemics & hemophiliacs.
Transmission: The low prevalence of HCV infection in childhood
is most probably because of the fact that the most common routes of
transmission by parenteral or percutaneous are less frequent in children
than is adults. The risk of infection through household contacts is low
(average 1.8%) although higher when the mother is the index case (about 3%)
and lower when it is the father (0.6%). In most cases it is not possible to
identify the risk factor or the route of infection. The overall risk of
vertical transmission has been estimated to be about 5% (0-25%). If the
mother is only anti HCV positive, the risk of vertical transmission varies
from 5-10%. This increases to 9-50% if she is HCVRNA positive. If the
mother is also HIV co infected then the transmission rate rises to 14%
(9-100%. The identification of fewer quasi species explains the mild form
of the disease the infants show. Most studies have indicated that caesarean
section does not decrease the risk of perinatal transmission of HCV but
rather increases in relation to the time between membrane rupture and
delivery.
Screening: All children with prolonged jaundice, multiple
blood transfusions, hemodialysis and recurrent injections should be
screened for HCV infection. Screening is not recommended for all pregnant
women. However all babies born to women sho are HCV positive should be
tested for infection. Testing for Anti HCV should be delayed for 12-18
months to allow for maternally derived IgG to clear from the blood of the
infant.
Natural History of Hepatitis C: The natural
history in children has not been established & varies in children from
adults because of different mode of transmission, age of acquisition and
immunological response. Progress to chronicity was seen in 90-100% of the
children of mothers with HCV infection who had elevated aminotransferase
levels & were HCVRN positive. The disease is milder in children. 40-50%
of the children after transfusion associated HCV infection clear the virus
& 20% remain asymptomatic.
Diagnosis: Diagnosis should be based on at least 2 serum
samples that are HCV RNA positive two months apart, with ALT levels. Anti
HCV should be tested only in children after the first year of life.
Screening should be based on a single 2nd or 3rd
generation EIA and a repeat 2 months later for confirmed positively.
Qualitative HCV RNA by PCR should be done for week positive EIA samples,
chronic liver disease of HCV, chronic hepatitis C with normal ALT and a in
diagnosis of vertical transmission.
Treatment:
At our center we have treated 16
children with chronic HCV (mean age range 7.1 yrs.). 14 were treated with
interferon alone while 2 were treated with a combination of IFN +
Ribavarin. There was sustained response in 25%. In 6 children repeat biopsy
were performed after 6 months to 2 years after therapy, showed significant
improvement in histological activity. Both the children on the combination
therapy showed response. Therapy had to be stopped in 2 children and one
child was lost in follow up.
There is not known intervention capable of
interrupting the spread of HCV from mother to child. In future we need
drugs that have greater specificity for HCV with less system side effects
and which are compatible with detection and quantification of HCV.
Vaccination:
HCV is a worthy adversary
changing continuously to avoid the surveillance by the host. A traditional
vaccine is unlikely to be effective and experiments with DNA based vaccines
offers a promising approach.