During a routine pediatric visit, a 12-month-old patient will need which of the following vaccines?

Correct Answer: B

Rationale: At 12 months, the CDC schedule includes Hib (dose 4), PCV (dose 4), MMR (dose 1), Varicella (dose 1), HepA (dose 1, with dose 2 at 18-24 months), and influenza (annually, 2 doses initially if first season). DTaP dose 4 is at 15-18 months, IPV dose 4 at 4-6 years, and RV completes by 8 months. Choice B matches the 12-15 month visit most closely. Choice C lacks MMR and Varicella, critical at this age.

Correct Answer: D

Rationale: Maternal antibodies, passed via the placenta (passive immunity), typically protect infants for about 6 months, though this varies by disease and antibody type (e.g., measles protection may last up to 12 months). None of the options (1, 2, or 5 years) accurately reflect this duration. 'None of the above' (Choice D) is correct, as the typical range is shorter than 1 year, often 3-6 months, per CDC and immunological data.

Correct Answer: C

Rationale: Rolling over occurs at 2-6 months, the earliest motor milestone listed (AAP). Crawling (6-12 months), walking (12-18 months), and speaking (words, 12 months) follow later, making Choice C correct.

Correct Answer: C

Rationale: Sickle cell anemia causes sickle cell crises (vaso-occlusive events) due to RBC sickling, per CDC. Choices A, B, and D are distinct conditions, not direct complications.

Correct Answer: C

Rationale: Monitoring vital signs assesses stability in intussusception, a priority before interventions (AAP). Pain meds (Choice A) and surgery prep (Choice B) follow; liquids (Choice D) are contraindicated.