A nurse is preparing to administer a vaccine to a 4-year-old child. Which of the following vaccines should the nurse administer?

Choice A reason: The posterior fontanel, which is the soft spot at the back of the infant's head, normally closes by 2 to 4 months of age. Therefore, the nurse should expect to find a closed posterior fontanel in a 6-month-old infant.

Choice B reason: Lateral incisors, which are the teeth on either side of the central incisors, normally erupt between 7 and 10 months of age. Therefore, the nurse should not expect to find lateral incisors in a 6-month-old infant.

Choice C reason: Sitting steadily without support is a developmental milestone that is usually achieved between 6 and 9 months of age. Therefore, the nurse may or may not expect to find this skill in a 6-month-old infant, depending on the individual variation.

Choice D reason: Using thumb and index fingers in a pincer grasp is a fine motor skill that is usually developed between 9 and 12 months of age. Therefore, the nurse should not expect to find this skill in a 6-month-old infant.

Choice A reason: Intravenous immunoglobulin is a likely prescription, as it is used to treat Kawasaki disease, which is a rare but serious condition that causes inflammation of the blood vessels in children. The toddler has many signs and symptoms of Kawasaki disease, such as high fever, irritability, red eyes, dry lips, strawberry tongue, swollen hands and feet, rash, and enlarged lymph node. Intravenous immunoglobulin can reduce the risk of complications, such as coronary artery aneurysms, which can be life-threatening.

Choice B reason: Oral acyclovir is not a probable prescription, as it is used to treat viral infections, such as herpes simplex or varicella zoster, which are not the main problems of the toddler. The toddler has no evidence of a viral infection, such as blisters, vesicles, or crusts.

Choice C reason: Intramuscular penicillin is not a likely prescription, as it is used to treat bacterial infections, such as streptococcal pharyngitis or syphilis, which are not the main problems of the toddler. The toddler has no signs of a bacterial infection, such as purulent discharge, foul odor, or localized inflammation.

Choice D reason: Topical hydrocortisone is not a helpful prescription, as it is used to treat skin conditions, such as eczema or dermatitis, which are not the main problems of the toddler. The toddler has a rash that is caused by the inflammation of the blood vessels, not by an allergic or irritant reaction. Topical hydrocortisone may also worsen the rash or cause skin thinning or infection.