Measles Outbreak with Unique Virus Genotyping, Ontario, Canada, 2015.

The province of Ontario continues to experience measles virus transmissions despite the elimination of measles in Canada. We describe an unusual outbreak of measles in Ontario, Canada, in early 2015 that involved cases with a unique strain of virus and no known association among primary case-patients. A total of 18 cases of measles were reported from 4 public health units during the outbreak period (January 25-March 23, 2015); none of these cases occurred in persons who had recently traveled.

Assessment of sex-specific differences in adverse events following immunization reporting in Ontario, 2012-15.

We assessed sex-specific trends within passive vaccine safety surveillance in Ontario, Canada. AEFIs reported following vaccines administered between 2012 and 2015 were included. There were 2466 AEFI reports; 66.

The epidemiology of invasive pneumococcal disease in older adults from 2007 to 2014 in Ontario, Canada: a population-based study.

Background: In Ontario, pneumococcal conjugate vaccines (PCVs) have been sequentially introduced into the publicly funded childhood vaccination program since 2005. A 23-valent polysaccharide pneumococcal vaccine (PPV23) has been routinely recommended for adults aged 65 years and older since 1996. To determine the effect of herd immunity, we examined the epidemiology of invasive pneumococcal disease in adults aged 65 years and older.

The Epidemiology of Invasive Haemophilus influenzae Non-Serotype B Disease in Ontario, Canada from 2004 to 2013.

Background: Since the widespread use of Haemophilus influenzae (Hi) type b (Hib) vaccines among children aged <5 years, an increase in invasive non-Hib disease incidence has been reported internationally. We sought to describe the epidemiology of invasive non-Hib disease in Ontario, Canada (population ~13.5 million).

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.

Background: Under Ontario legislation, for select vaccine-preventable diseases nonimmunized or under-immunized students must undergo vaccination or provide a statement of exemption, or risk suspension from school. At the time of this assessment, these diseases included measles, mumps, rubella, diphtheria, tetanus and polio.

Methods: Exemptions data for the school years 2002/03 to 2012/13 were obtained from the Immunization Records Information System used in Ontario.

Vaccine safety implications of Ontario, Canada's switch from DTaP-IPV to Tdap-IPV for the pre-school booster.

Ontario, Canada, replaced the 4-6 year old diphtheria (D, d), tetanus (T), acellular pertussis (aP, ap) and polio (IPV) booster from DTaP-IPV to Tdap-IPV in May 2012. We assessed the impact of this replacement on the rate and types of reported adverse events following immunization (AEFIs). We used AEFIs reported among 4-6 years olds, through the provincial surveillance system, following administration of DTaP-IPV or Tdap-IPV from 2009 to 2013.

Adverse events following immunization in Ontario's female school-based HPV program.

Background: In September 2007, a school-based human papillomavirus (HPV) vaccination program targeting grade 8 girls (approximately 13 years old) and delivered by public health was implemented in Ontario, Canada. We assessed reports of adverse events following immunization (AEFI) from the school-based program as part of quadrivalent HPV (HPV4) vaccine safety surveillance and to contribute to a comprehensive HPV vaccine program evaluation.

Methods: AEFIs following HPV4 vaccine (Gardasil(®)) administered between September 1, 2007 and December 31, 2011 were extracted from the province's reportable disease system.

Coverage from Ontario, Canada's school-based HPV vaccine program: the first three years.

Background: In 2007, Ontario implemented a school-based human papillomavirus (HPV) vaccination program targeting grade 8 girls. Girls may complete the series in grade 9 (extended eligibility). Limitations in the existing provincial data sources for assessing HPV vaccine coverage in Ontario prompted the use of two surveys of Health Units (HUs) to calculate provincial vaccine coverage for the first three years of the vaccination program.