Which vaccine is administered orally to a 4-month-old infant?

• A. IPV
• B. DTaP
• C. Rotavirus
• D. Haemophilus influenzae type B (HIB)

Answer: (C)

Rotavirus vaccine is given by mouth, making it the only oral option among these vaccines. In infancy, this oral, live attenuated vaccine is started around 2 months of age and given in a short series (two or three doses depending on the product), with all doses completed by about 8 months. The other vaccines listed—IPV, DTaP, and Hib—are administered by injection (intramuscular or subcutaneous), not orally. So at 4 months, the vaccine given orally is Rotavirus, which protects against rotavirus gastroenteritis.