A single serum specimen collected at first contact with the health care system is sufficient for confirming measles. Suspected measles cases, with epidemiologic links to laboratory confirmed cases are themselves considered to be laboratory confirmed. Cases meeting the clinical case definition but which have neither laboratory confirmation nor epidemiologic links to a laboratory confirmed case represent failures of the surveillance system. A positive result can be considered confirmatory of measles. Specimens that present special problems can still be sent to regional reference laboratories for confirmation by the CDC capture IgM assay.
Virologic surveillance is important.
Clinical specimens for viral isolation should be obtained from every chain of transmission. Urine, the most practical specimen to collect, should be obtained within 7 days of rash onset and forwarded to a laboratory to be properly processed. If more than one birth cohort of susceptible preschool children has accumulated in an outbreak area, a mass campaign should be promptly conducted. All schoolchildren should be screened and all those who have not received at least one dose of vaccine should be vaccinated. All children presenting to a hospital emergency room or other health care facility during a measles outbreak should be vaccinated, regardless of prior vaccination status, provided there are no contraindications.