PLE-4279

A 32-year-old woman, who is 38 weeks pregnant, comes for a routine prenatal visit. During routine screening at 28 weeks of gestation, she tested positive for hepatitis B surface antigen. Her pregnancy has been otherwise uncomplicated. Examination shows a uterus consistent in size with a 38-week gestation. Which of the following measures is most likely to decrease the risk for hepatitis B infection in her newborn?