Exemptions for Ontario kids not vaccinated for measles stays low
But data shows religious/conscientious objections increasing while medical exemptions decrease
New research from Public Health Ontario
(PHO) shows that rates of parents choosing not to immunize their kids for measles based on religious or conscientious objections is increasing. However, the total number of children not getting vaccinated due to exemptions remains low across the province.
Measles is one of the most contagious vaccine-preventable diseases. The measles virus can live for up to two hours in the air where an infected person has coughed or sneezed, and a person can transmit the virus to others four days before and four days after the appearance of the rash. Symptoms include fever, red rash on the skin, white spots in the mouth, and complications in up to 25 per cent of cases.
Under Ontario legislation, for certain vaccine-preventable diseases, students who are not immunized or who are missing doses, must provide either their immunization records or register a statement of exemption, or else risk being suspended from school. During the research period studied, those immunizations included measles, mumps, rubella, diphtheria, tetanus and polio. In a new CMAJ Open paper, titled Trends in medical and nonmedical immunization exemptions to measles-containing vaccine in Ontario: an annual cross-sectional assessment of students from school years 2002-03 to 2012-13
, researchers at PHO examined immunization exemption records to gain a greater understanding of the size and trends of vaccine hesitancy with respect to measles.
“Vaccine hesitancy is an ongoing concern and there is limited published research studying nonmedical exemptions in Canada,” says Dr. Sarah Wilson
, public health physician in immunization and vaccine-preventable disease at PHO and lead author on the study. “Looking at 11 years of Ontario immunization records for 7- and 17-year-olds, we found that the rate of exemptions for religious or conscientious objections for measles-containing vaccines significantly increased over the study period while the rate for medical exemptions significantly decreased.
“That said, it’s important to note that the percentage of nonmedical exemptions was still quite low – less than two per cent – although we did see geographic variation across the province,” adds Wilson, who conducted the research with PHO colleagues. Wilson is also an assistant professor at the University of Toronto’s Dalla Lana School of Public Health.
When assessed by trends across school years, exemptions for conscientious or religious beliefs among 7-year-old students increased from 1.05 per cent in the 2002-03 school year to 1.54 per cent in 2012-13; medical exemptions decreased from 0.51 per cent to 0.16 per cent over the same period. Similar trends were noted for 17-year-olds.
“This research helps us understand the numbers of children who are not benefiting from vaccines, like the MMR vaccine,” notes Dr. Shelley Deeks
, medical director of immunization and vaccine-preventable disease at PHO and a co-author on the study. “We need to better understand why parents are making the decision not to vaccinate their children, as the evidence shows vaccines are safe and effective in preventing disease.”
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