Dr D Gibb and colleagues from London, England investigated 441 mother-child pairs. They examined the factors affecting the rates of vertical Hepatitis C virus transmission and identified the likely time of transmission.
Using data from three major UK centers, they followed the maternal antibody clearance in non-infected infants and evaluated the accuracy of PCR technology.
Antibodies persisted in 50% of non-infected infants for 8 months, with clearance levels increasing to 95% by 13 months.
PCR testing for HCV RNA, 97% specific, was found to increase in sensitivity from 22% to 97% after the first month of life.
"If findings on Caesarian section are confirmed, the case for antenatal HCV testing should be reconsidered."
Maternal HIV coinfection significantly increased the rate of vertical transmission from 6.7% to around 25%; however breastfeeding had no effect on transmission after birth.
Caesarian section, in an elective setting with intact placental membranes, significantly decreased the rate of transmission.
Dr Gibb emphasizes the protective nature of elective Caesarian birth, and the low initial maternal HCV antibody levels in non-infected infants. Together, they suggest a transmission time and mode related to delivery, and contact between fetal and maternal blood.