Methods
Samples and epidemiological data
Case-based surveillance of measles is conducted continuously
in Norway. The case definition used in the
present study was based on the WHO classification
of measles cases [16]. In Norway, the WHO National
Reference Laboratory for Measles and Rubella is
located at the Norwegian Institute of Public Health
(NIPH) where samples obtained from suspected and
notified measles cases are routinely sent for confirmation.
All laboratory-confirmed cases are reported to the
surveillance system. Healthcare personnel who suspect
a measles case are required to notify the NIPH via
the institute’s 24-hour call centre, and then send the
samples directly to the NIPH reference laboratory to
be analysed immediately to expedite the public health
response. Thirty-three notified cases in Norway in 2011
were investigated at the NIPH. The information during
the case investigation was collected by telephone
interview and included demographic characteristics,
ethnic background, clinical symptoms, hospitalisation,
vaccination status, travel history and laboratory data.
Contact tracing is also routinely undertaken, especially
for unvaccinated and exposed individuals.