The Parent of a Toddler and a 4-Week-Old Infant Tells

The parent of a toddler and a 4-week-old infant tells the primary care pediatric nurse practitioner that the toddler has just been diagnosed with pertussis. What will the nurse practitioner do to prevent disease transmission to the infant?

A) Administer the initial diphtheria, pertussis, and tetanus vaccine.
B) Instruct the parent to limit contact between the toddler and the infant.
C) Order azithromycin 10 mg/kg/day in a single dose daily for 5 days.
D) Prescribe erythromycin 10 mg/kg/dose four times daily for 14 days.