Improving global virologic surveillance for measles and rubella.

An important aspect of laboratory surveillance for measles and rubella is the genetic characterization of circulating wild-type viruses to support molecular epidemiologic studies and to track transmission pathways. Virologic surveillance that is sufficient to document the interruption of transmission of measles and rubella viruses will be an essential criterion for verification of elimination. Laboratories in the World Health Organization (WHO) Measles and Rubella Laboratory Network have worked to improve and expand virologic surveillance as many regions move toward elimination of measles and rubella/congenital rubella syndrome. As countries approach elimination, it will be necessary to obtain genetic information from as many chains of transmission as possible. In addition, baseline virologic surveillance, especially for rubella, needs to be improved in many countries. This report contains a summary of recent improvements to the methods used for virologic surveillance.