Final answer:
When admitting a school age child with pertussis, the nurse should place the child in a negative-pressure isolation room to prevent the spread of the disease.
Step-by-step explanation:
When admitting a school age child with pertussis, the nurse should take several actions to ensure the child's safety and prevent the spread of the disease. Option B, placing the child in a negative-pressure isolation room, is the most appropriate action to take in this situation. This type of room helps to prevent the airborne transmission of pertussis by containing and filtering the infectious particles.
Administering a live attenuated vaccine (option A) is not appropriate for a child who already has pertussis, as the vaccine is not effective in treating an active infection. Option C, encouraging outdoor activities for ventilation, is not necessary for the treatment of pertussis. And option D, administering antipyretics to reduce fever, may be done as needed to alleviate symptoms, but it does not address the main concern of isolation and prevention of transmission.