This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Concepts of Immunity, Classification of Vaccines, Subject name: Social & Preventive Medicine
[{'content': 'Due to a measles outbreak within a community, a 7 month old male child was vaccinated for measles. what should be done next when the child comes for routine immunization? \nSelect and explain. \nA. Give a second dose after 6 weeks., B. Give a second dose as soon as he reaches 9 months of age., C. Give the second dose of measles at 16 months of age, D. Give the second dose of measles at 12 months of age.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Vaccine can be given to a child between 6-9 months old during measles epidemic as till 6 months maternal antibodies provide immunity. For infants immunized during epidemic, a second dose should be administered as soon as possible after the child reaches the age of 9 months provided that at least 4 weeks have elapsed since the last dose', 'role': 'assistant'}]