Outbreak of measles in a non-immunizing population, Alberta 2013

An outbreak of measles was declared in southern Alberta on October 18, 2013, after a case had been reported to the local public health unit in a non-immunized teenager with recent travel to the Netherlands. The teenager had had contact with a large number of unimmunized people while infectious; therefore, the risk of spread was high. The potential for an outbreak of measles in this area had been identified by the lead Medical Officer of Health for South Zone, and planning for an outbreak had begun in August 2013.

Several public health measures were implemented to control the outbreak: mass immunization clinics; an outbreak dose of measles mumps and rubella (MMR) vaccine for infants 6-12 months old; communication within the affected and surrounding communities; a dedicated measles hotline; a Mobile Measles Assessment Team; and a Measles Assessment Centre.

A total of 42 confirmed cases were identified during the outbreak between October 16 and November 25. Just over half the cases were male (52.4%). The average age was 12 (range < 1 to 24 years) and the median age 13 years. There was one hospitalization, and no deaths occurred. All cases were unimmunized. Cases were located in five communities immediately surrounding Lethbridge. All but two cases were epidemiologically linked within 10 households.

The planning that occurred before the outbreak was essential in containing the outbreak to 10 households. To prevent future outbreaks of measles, exploring strategies for increasing immunization coverage rates in unimmunized populations is essential. When immunization acceptance is not uniform, other public health strategies should be planned for and implemented in order to prevent additional spread.