Validation of infant immunization billing codes in administrative data.

Ontario has a single payer provincial health insurance program. Administrative data may provide a potentially robust source of information for post-marketing vaccine studies. Vaccine-specific immunization billing codes were introduced in 2011. Our objective was to validate Ontario's universal health care administrative datasets to assess infant immunization status. Electronic medical record data from the Electronic Medical Record Administrative data Linked Database (EMRALD) was used as the reference standard to calculate performance characteristics of the Ontario Health Insurance Plan (OHIP) database vaccine-specific and general immunization codes for 4 primary infant immunizations: diphtheria, tetanus, acellular pertussis, inactivated polio, Haemophilus influenzae type B (DTaP-IPV-Hib) combination vaccine, pneumococcal conjugate vaccine, measles, mumps, rubella (MMR) vaccine, and meningococcal conjugate serogroup C vaccine. OHIP billing claims had specificity ranging from 81% to 92%, sensitivity 70% to 83%, positive predictive value (PPV) 97% to 99%, and negative predictive value (NPV) 13% to 46% for identifying the various specific vaccines in administrative data. For cohorts vaccinated in the new code introduction phase, using both the vaccine-specific and general codes had higher sensitivity than the vaccine-specific codes alone. In conclusion, immunization billing claims from administrative data in Ontario had high specificity and PPV, moderate sensitivity, and low NPV. This study identifies some of the applications of utilizing administrative data for post-marketing vaccine studies. However, limitations of these data decrease their utility for measuring vaccine coverage and effectiveness. Therefore, the establishment of a comprehensive and linkable immunization registry should be a provincial priority.

pH1N1 - a comparative analysis of public health responses in Ontario to the influenza outbreak, public health and primary care: lessons learned and policy suggestions.

BACKGROUND: Ontario's 36 Public Health Units (PHUs) were responsible for implementing the H1N1 Pandemic Influenza Plans (PIPs) to address the first pandemic influenza virus in over 40 years. It was the first under conditions which permitted mass immunization. This is therefore the first opportunity to learn and document what worked well, and did not work well, in Ontario's response to pH1N1, and to make recommendations based on experience. METHODS: Our objectives were to: describe the PIP models, obtain perceptions on outcomes, lessons learned and to solicit policy suggestions for improvement. We conducted a 3-phase comparative analysis study comprised of semi-structured key informant interviews with local Medical Officers of Health (n=29 of 36), and Primary Care Physicians (n=20) and in Phase 3 with provincial Chief-Medical Officers of Health (n=6) and a provincial Medical Organization. Phase 2 data came from a Pan-Ontario symposium (n=44) comprised leaders representing: Public Health, Primary Care, Provincial and Federal Government. RESULTS: PIPs varied resulting in diverse experiences and lessons learned. This was in part due to different PHU characteristics that included: degree of planning, PHU and Primary Care capacity, population, geographic and relationships with Primary Care. Main lessons learned were: 1) Planning should be more comprehensive and operationalized at all levels. 2) Improve national and provincial communication strategies and eliminate contradictory messages from different sources. 3) An integrated community-wide response may be the best approach to decrease the impact of a pandemic. 4) The best Mass Immunization models can be quickly implemented and have high immunization rates. They should be flexible and allow for incremental responses that are based upon: i) pandemic severity, ii) local health system, population and geographic characteristics, iii) immunization objectives, and iv) vaccine supply. CONCLUSION: "We were very lucky that pH1N1 was not more severe." Consensus existed for more detailed planning and the inclusion of multiple health system and community stakeholders. PIPs should be flexible, allow for incremental responses and have important decisions (E.g., under which conditions Public Health, Primary Care, Pharmacists or others act as vaccine delivery agents.) made prior to a crisis.