Correlation between paternal serum hepatitis B virus DNA levels and vertical transmission from father to infant

This study aimed to investigate the relationship between paternal serum hepatitis B virus (HBV)DNA levels and father to infant vertical transmission. A total of 202 couples with mothers who tested positive for prenatal hepatitis B surface antibody (anti-HBs) were included in the observation group, while 196 couples with mothers who tested negative for prenatal anti-HBs were included in the control group. Fathers within the two groups were further divided into four groups (10e9-10e6 IU/ml, 10e6-10e4 IU/ml, 10e4-10e2 IU/ml, <10e2 IU/ml) based on their HBVDNA levels. HBV serologic markers (HBVM) and HBVDNA were detected by electrical chemiluminescence immunoassay and fluorogenic quantitative PCR, respectively. In the observation group, nine newborns (9/53) tested positive for HBVDNA as determined by testing the umbilical cord blood in the group where paternal serum HBV-DNA levels were 10e9-10e6 IU/ml. One infant (1/51) was positive for HBVDNA from the group where the paternal serum HBV load ranged from 10e6-10e4. The difference in rate of transmission between these two groups was statistically significant. There were no infants positive for HBVDNA in the other two groups where the fathers were HBV carriers with viral loads of less than 10e4 IU/ml. In the control group, eleven infants (11/52) were tested positive for HBVDNA using umbilical cord blood in the group where the paternal serum HBVDNA level was 10e9-10e6 IU/ml. Three neonates (3/50) were positive for HBVDNA in the group where the paternal serum HBVDNA load was in the range of 10e6-10e4 IU/ml. The difference in rate of transmission between these two groups was statistically significant. One case (1/52) tested positive for HBVDNA in the group where the paternal serum HBVDNA level was in the range of 10e4-10e2 IU/ml, This rate of transmission was not significantly different from that of the group with paternal serum HBVDNA levels in the range of 10e6-10e4 IU/ml. HBVDNA was not detected in newborns with paternal serum HBVDNA levels of less than 10e2 IU/ml. These results demonstrated that the HBV vertical transmission rate was positively correlated with the paternal serum HBVDNA level. Moreover, the father to fetus vertical transmission of HBV could not be blocked completely in the presence of high paternal serum HBV viral loads, even if the mother was positive for anti-HBs. The sample size of this study is small, and thus, more investigations on the stratification of prenatal anti-HBs status are required based on a larger sample size.