Dr. Jourdain and his colleagues noted that the 2% transmission rate in the placebo group is considerably lower than the 7% seen in similar studies and could be related to the rapid postpartum administration of HBV immune globulin and vaccine. If this is the case, prenatal antivirals could be more effective in countries where postpartum treatment is delayed or inconsistent.
“Maternal use of tenofovir may prevent transmissions that would occur when the birth dose is delayed, but its exact timing has not been reported consistently in previous perinatal studies,” the team said.
Another question is whether the stringent, 5-dose infant HBV vaccine series required in Thailand is simply more effective than schedules that have fewer doses or are combined with other vaccines and delivered later.
“It remains unclear whether the administration of more vaccine doses is more efficacious than the administration of the three vaccine doses that is recommended in the United States and by the World Health Organization.”
Dr. Jourdain had no financial disclosures relevant to the study, which was sponsored by the National Institute of Child Health and Human Development.
SOURCE: Jourdain G et al. N Engl J Med. 2018;378:911-23.