What is the recommended site for intramuscular vaccination in infants?

• A. Deltoid muscle.
• B. Vastus lateralis (anterior-lateral thigh).
• C. Gluteus maximus.
• D. Rectus abdominis.

Answer: (B)

Infants have a small deltoid and limited muscle mass in the buttocks, so the safest and most reliable IM vaccine site is the muscle on the front of the thigh. The vastus lateralis, located on the anterolateral thigh, provides thicker muscle tissue with fewer major nerves and vessels in that area, making injections both safer and better absorbed. Injections into the gluteal region risk injury to the sciatic nerve and can be inconsistent in infants, while the abdominal rectus area is not used due to potential injury to underlying organs. So, the recommended site for intramuscular vaccination in infants is the vastus lateralis in the anterior-lateral thigh.