This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
[{'content': 'Vaccination causing intussusception is \nSelect and explain. \nA. Rotavirus, B. Parvovirus, C. Poliovirus, D. BCG', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Rotavirus vaccination - there is a potentially high risk of intussusception with the first dose when this vaccine is given to infants aged more than 12weeks. Ref: Park&;s textbook of preventive and social medicine; 23rd edition.', 'role': 'assistant'}]