Discrepancy in impact of maternal milk on vertical transmission between Hepatitis B virus and Human cytomegalovirus

• Discrepancy exists in vertical transmission via maternal milk between HBV and HCMV
• Breastfeeding is not a reason for vertical transmission of HBV
• Lower HBV transmission is attributed primarily to hepatitis B vaccination and HBIG
• Breast milk with viral DNA is a main source for vertical transmission of HCMV
• There are some measures to be taken to prevent and control HCMV infection

SummaryObjectivesThis study aims to elucidate the role of breastfeeding on vertical transmission of HCMV and HBV and to investigate the difference in perinatal transmission via breast milk between HBV and HCMV.MethodsThis detailed study monitored the kinetics of viral DNA load in maternal milk for both HBV and HCMV, demonstrated the rate of transmission to infants, and compared HBV infection rate with that of HCMV.ResultsThere was no difference in overall DNAlactia+ between HBV (23.86%) and HCMV (29.54%, P=0.140) for seropositive mothers, while HBsAg prevalence (0.75%) was significantly lower than HCMV IgG+ (27.44%, P<0.001) for the breast-fed babies. Between breast-fed babies of seropositive mothers and those of seronegative mothers, HBV infection rate had no difference (HBsAg+: 0.75% vs 0%, P=0.538; DNAemia+: 0.38% vs 0%, P=0.664), but HCMV infection rate of the former was significantly higher than that of the latter (IgG+: 27.07% vs 18.00%, P=0.045; DNAemia+: 15.79% vs 4.00%, P=0.027).ConclusionsBreastfeeding is not a risk factor for maternal-to-infant transmission of HBV after the recommended prophylaxis is implemented. However, viral DNA positive breast milk is a main source for vertical transmission of HCMV to infants who are not protected by a standard immunoprophylaxis protocol.