Background: There has been a resurgence of mumps, measles and rubella in many parts of the developed world, particularly among older children and young adults. This is due to these age groups experiencing a decline in natural exposure to these viruses as a result of past successful vaccination programs, and the current lower vaccination uptake in some communities. One factor behind reluctance to vaccination is the lack of awareness about the risk of infection and the seriousness of the disease. This paper describes three outbreaks initiated by international travel in a country with high quality of health care, but pockets of insufficient vaccination coverage for the MMR vaccine. Methods: The epidemiology of three distinct outbreaks within the same local health authority between 2010 and 2011 are described in terms of case demographics, immunisation status and setting. Results: In all three outbreaks, the majority of cases were young adults who were either unimmunised or received only one dose of measles, mumps or rubella vaccine. Following the winter Olympics twenty-one cases of locally-acquired measles were identified with two geographically distinct genotypes (H1 and D8). Second, an outbreak of rubella in a workplace was identified (n = 7). The index case had travelled to their country of origin where the disease is still endemic and on their return worked while infectious. Third, an outbreak of mumps occurred among international seasonal workers at a resort community. A total of 108 cases were identified before successful control in the community of origin via targeted immunisation. Conclusion: These outbreaks confirm the existence of susceptible groups that require additional targeted strategies to achieve >95% coverage and thereby increase immunity levels in the population beyond that provided by routine childhood immunization. Alongside the need for high vaccination coverage, these outbreaks highlight the need to maintain effective disease surveillance that permits timely implementation of outbreak control measures. In the context of international travel, mass gathering events, immigrants visiting countries of origin and transient foreign workers can all initiate introductionof pathogens that are uncommon to the host country. This compounded by the silent accumulation of susceptible individuals facilitate transmission resulting in community outbreaks.
Sandhu, J., Leung, T., LaFlamme, E., Martiquet, P., & Gustafson, R. (2012). Outbreaks of mumps, measles and rubella in British Columbia, Canada. International Journal of Infectious Diseases, 16, e360. https://doi.org/10.1016/j.ijid.2012.05.451