Detection of measles vaccine in the throat of a vaccinated child.

Measles vaccine is widely used, most often in association with mumps and rubella vaccines. We report here the case of a child presenting with fever 8 days after vaccination with a measles-mumps-rubella vaccine. Measles virus was isolated in a throat swab taken 4 days after fever onset. This virus was then further genetically characterised as a vaccine-type virus. Fever occurring subsequent to measles vaccination is related to the replication of the live attenuated vaccine virus. In the case presented here, the vaccine virus was isolated in the throat, showing that subcutaneous injection of an attenuated measles strain can result in respiratory excretion of this virus.