A nurse is preparing to administer vaccines to a 12-year-old. Which action is most appropriate?

A. Use the vastus lateralis for IM injections: The vastus lateralis is preferred in infants and toddlers due to well-developed muscle mass in the thigh. By 12 years old, this site is generally less appropriate because the deltoid has sufficient muscle for intramuscular injections. B. Combine all vaccines into one syringe to minimize sticks: Mixing vaccines in a single syringe is not recommended, as it may alter vaccine efficacy, increase the risk of local reactions, or lead to improper dosing. Each vaccine should be administered separately, following recommended spacing and sites. C. Use the deltoid for IM injections: The deltoid muscle is the preferred intramuscular injection site for children over 3 years of age who have adequate muscle mass. It allows for safe absorption of vaccines and minimizes the risk of injury to nerves or blood vessels, making it appropriate for a 12-year-old. D. Delay vaccines if the child is teething: Teething is not a contraindication to immunization. Vaccines should be administered according to schedule, and minor discomfort from teething does not affect immune response or safety.