Hepatitis B in the Lactating Parent
by Anne Eglash MD, IBCLC, FABM
Chronic HBV infection is the major cause of liver cirrhosis and liver cancer, with approximately 887,000 deaths in 2015 from complications of HBV infection.
Hepatitis B is spread via bodily fluids, such as sexual contact, sharing needles or exposure to infected needles via tattooing/acupuncture/piercing, or sharing toothbrushes, razors, or other personal items with someone who has HBV infection.
Maternal-child transmission (MTCT) is responsible for 50% of cases of HBV, either during pregnancy, delivery or postpartum. Most chronic HBV cases are in China, however it is estimated that 0.7-0.9% of pregnant women in the USA test positive for HBV.
Chinese researchers for this week’s study sought to evaluate the viral load of HBV in the serum of the lactating parent, the DNA load of HBV in human milk, and the MTCT rate of HBV based on feeding method.
The researchers followed a cohort of pregnant women living with chronic HBV infection. The infants were divided between breastfeeding (exclusive and mixed feeding) n= 214, and formula feeding n=223. The mothers were stratified by their serum viral load of HBV; negative, low (5x102-1x106copies/ml), and high (> 1x106 copies/ml).
All newborns were given passive immunization of hepatitis B immunoglobulin (antibodies against hepatitis B) within 2 hours of birth and again on day of life 30. They all received the hepatitis B immunization series on day of life 1, day of life 30, and at 6 months of age. After finishing the immunization series, the infants were checked for immune response and if they had no or low antibody response, they were given a booster.
All infants were followed up to 1-2 years of age, and then tested for HBV infection.
The researchers found that 1 breastfed and 2 formula-fed children of mothers with negative HBV DNA titers were positive for HBV infection. None of the children of mothers with low HBV DNA titers tested positive for HBV infection. However, 7 children of mothers with high DNA titers tested positive for HBV infection, 6 breastfed and 1 formula-fed.
The authors recommended that pregnant mothers living with high serum DNA titers of HBV infection (>1x 106 copies/ml) have shared decision making about a possible increased risk of transmitting HBV infection via breastfeeding.
- Higher serum DNA titers of HBV were associated with higher levels of HBV DNA in breastmilk.
- For mothers with high serum DNA titers of HBV, higher DNA titers of HBV were found in colostrum than in mature milk.
- There was no significant difference in immune response to the HBV vaccine between the breastfed and formula fed infants.
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This study aims at researching the content of hepatitis B virus (HBV) DNA in the breast milk of the mothers carrying HBV and investigating the effects of different feeding methods on mother-to-child transmission (MTCT) of HBV.
All infants were voluntarily chosen by their mothers and divided into breast-feeding group and formula-feeding group, which were divided into three subgroups, respectively: HBV-DNA negative (HBV-) group, low viral load (LVL) group and high viral load (HVL) group.
HBV load in colostrum and mature milk were both significantly lower than in serum (P < 0.001). The positive rate of HBV-DNA in colostrum was positively correlated with HBV load in serum, significantly higher than that of the HBV-Group in colostrum in the LVL Group (P < 0.05), and the HVL Group was significantly higher than the LVL Group (P < 0.001). The analysis of risk factors of HBV infection in infants showed that breast-feeding and HBsAg positive in colostrum did not increase the risks of HBV infection of infants (P > 0.05).
Breast-feeding is safe for infants with HBV-infected mothers who receive active immunization combined with passive immunization. As well, breast-feeding will neither increase the risks of HBV infection for infants nor weaken their immunity to HBV. However, breast-feeding shall be cautiously applied to pregnant women with high viral load.
These authors summarized that higher maternal HBV serum DNA loads, >1x106, was associated with a greater burden of HBV DNA in breastmilk. They also measured a higher positivity rate of HBV infection among breastfed infants of mothers with a high serum HBV DNA load as compared to formula fed infants.
The authors did not include the recommendation by the US Centers for Disease Control and the Society for Maternal-Fetal Medicine for antiviral therapy during the third trimester for pregnant individuals with high HBV DNA loads. If the level of HBV DNA in colostrum and human milk is related to the parent’s serum DNA level, then antiviral therapy during the third trimester, which has shown to lower the serum DNA load during pregnancy, may decrease any risk of transmission via breastfeeding.
The authors also pointed out that duration of effectiveness of passive immunity with hepatitis B immunoglobulin is approximately 42-63 days, which is before the infant is done with the hepatitis B vaccine series. In this study, all infants received hepatitis B immunoglobulin therapy right after birth and on day 30 of life. That is not the recommendation from the US Immunization Practices Advisory Committee. If there is a higher risk of HBV viral transmission among breastfed infants of parents with higher serum DNA load, and viral transmission could occur through bleeding nipples, perhaps a second or third hepatitis B immunoglobulin treatment is needed until the infants finish their vaccine series and demonstrates immunity to the vaccine.