Local public health response to vaccine-associated measles: case report
1 Peel Public Health, 7120 Hurontario St. RPO Streetsville, P.O Box 667, Mississauga, ON, L5M 2C2, Canada
2 Dalla Lana School of Public Health, University of Toronto, 155 College St, 6th floor, Toronto, ON, M5T 3M7, Canada
3 Department of Pediatrics, Faculty of Medicine, University of Toronto, 1 King’s College Circle, Toronto, ON, M5S 1A8, Canada
4 Division of Infectious Diseases, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada
5 Public Health Ontario, 480 University Avenue, Suite 300, Toronto, ON, M5G 1V2, Canada
6 National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, MB, R3E 3E2, Canada
7 Department of Microbiology and Infectious Diseases, Faculty of Medicine, University of Manitoba, Rm 543 – 745, Bannatyne Avenue, Winnipeg, MB, R3E 0J9, Canada
BMC Public Health 2013, 13:269 doi:10.1186/1471-2458-13-269Published: 25 March 2013
The most appropriate public health approach to vaccine-associated measles in immunocompromised patients is unknown, mainly because these cases are rare and transmission of vaccine-associated measles has not been previously documented. In this case report, we describe Peel Public Health’s response to a vaccine-associated measles case in an immunocompromised child in Ontario, Canada.
A five-year-old Canadian-born boy with a history of a hematopoetic stem cell transplant three years previously received live attenuated measles, mumps, and rubella (MMR) vaccine. Over the subsequent 7 to 14 days, he developed an illness clinically consistent with measles. There was no travel history or other measles exposure. Serology and polymerase chain reaction (PCR) testing confirmed acute measles infection. Following discussion with pediatric infectious diseases specialists, but prior to the availability of virus sequencing, it was felt that this case was most likely due to vaccine strain. Although no microbiologically confirmed secondary cases of vaccine-associated measles have been previously described, we sent notification letters to advise all contacts of measles symptoms since the likelihood of transmission from an immunocompromised patient was low, but theoretically possible. We decided to stratify contacts into immune competent and compromised and to deal with the latter group conservatively by excluding them as if they were exposed to wild-type measles because the risk of transmission of disease in this population, while presumably very low, is unknown. However, no contacts self-identified as immunocompromised and there were no secondary cases. Subsequent genotyping confirmed that this case was caused by vaccine strain measles virus.
The public health approach to contact tracing and exclusions for vaccine-associated measles in immunocompromised patients is unclear. The rarity of secondary cases provides further evidence that the risk to the general public is likely extremely low. Although the risk appears negligible, exclusion and administration of immune globulin may be considered for susceptible, immunocompromised contacts of cases of vaccine-associated measles in immunocompromised patients.