A 30-year-old G2P1 woman at 26 weeks gestation presents to clinic because her 6-year-old child developed a diffuse vesicular rash and fever yesterday and was diagnosed with varicella. The patient has no history of chickenpox and is unsure whether she has ever been vaccinated. She feels well and has no rash. Prenatal course has been uncomplicated, and she takes only prenatal vitamins. What is the most appropriate post-exposure management for this patient?

(Assume she has no evidence of prior immunity.)