A multisite study of pertussis vaccine effectiveness by time since last vaccine dose from three Canadian provinces: A Canadian Immunization Research Network study.

Background: Pertussis remains poorly controlled relative to other diseases targeted by childhood vaccination programs. We combined estimates from four population-based studies of pertussis vaccine effectiveness (VE) in three Canadian provinces using a meta-analytic approach to improve precision and explore regional variation in VE and durability of protection.

Methods: Studies were conducted in Alberta, Manitoba, and Ontario over periods ranging from 1996 to 2015.

Using population-wide administrative and laboratory data to estimate type- and subtype-specific influenza vaccine effectiveness: a surveillance protocol.

Introduction: The appropriateness of using routinely collected laboratory data combined with administrative data for estimating influenza vaccine effectiveness (VE) is still being explored. This paper outlines a protocol to estimate influenza VE using linked laboratory and administrative data which could act as a companion to estimates derived from other methods.

Methods And Analysis: We will use the test-negative design to estimate VE for each influenza type/subtype and season.

The association between influenza vaccination and socioeconomic status in high income countries varies by the measure used: a systematic review.

Background: The purpose of this paper is to systematically review the literature on the relationship between socioeconomic status (SES) and influenza immunization and to examine how certain measures of SES may influence interpretations of this relationship.

Methods: We conducted a systematic review of existing peer-reviewed literature to evaluate the above relationship in the general population. Electronic databases (MEDLINE and EMBASE) were searched from January 2012 to May 2017 to identify English-language studies relevant to this review.

Estimating Vaccine Effectiveness Against Hospitalized Influenza During Pregnancy: Multicountry Protocol for a Retrospective Cohort Study.

Background: Although pregnant women are believed to have elevated risks of severe influenza infection and are targeted for influenza vaccination, no study to date has examined influenza vaccine effectiveness (IVE) against laboratory-confirmed influenza-associated hospitalizations during pregnancy, primarily because this outcome poses many methodological challenges.

Objective: The Pregnancy Influenza Vaccine Effectiveness Network (PREVENT) was formed in 2016 as an international collaboration with the Centers for Disease Control and Prevention; Abt Associates; and study sites in Australia, Canada, Israel, and the United States. The primary goal of this collaboration is to estimate IVE in preventing acute respiratory or febrile illness (ARFI) hospitalizations associated with laboratory-confirmed influenza virus infection during pregnancy.

Are we speaking the same language? an argument for the consistent use of terminology and definitions for childhood vaccination indicators.

Vaccination indicators are used to measure the health status of individuals or populations and to evaluate the effectiveness of vaccination programs or policies. Ensuring that vaccination indicators are clearly and consistently defined is important for effective communication of outcomes, accurate program evaluation, and comparison between different populations, times, and contexts. The purpose of this commentary is to describe commonly used vaccination indicators and to highlight inconsistencies in how childhood vaccine researchers use and define these terms.

Vaccine coverage of children in care of the child welfare system.

Objective: To assess vaccine coverage for a cohort of children who have been in the care of the child welfare system compared to children in the general population.

Methods: This retrospective cohort study used population-based administrative health data for a 2008 birth cohort of children from Alberta, Canada. We assessed coverage at ages 2 (n = 44,206) and 7 (n = 42,241) for three vaccines with different administration schedules for children in care (at any period before the age of assessment) and those who had never been in care, comparing them using risk differences and relative risks (RRs).

Effectiveness of Live Attenuated vs Inactivated Influenza Vaccines in Children During the 2012-2013 Through 2015-2016 Influenza Seasons in Alberta, Canada: A Canadian Immunization Research Network (CIRN) Study.

Importance: Recent observational studies report conflicting results regarding the effectiveness of live attenuated influenza vaccine (LAIV), particularly against influenza A(H1N1)pdm09.

Objective: To compare the effectiveness of LAIV and inactivated influenza vaccine (IIV) against laboratory-confirmed influenza.

Design, Setting, And Participants: A test-negative study to estimate influenza vaccine effectiveness (VE) using population-based, linked, individual-level laboratory, health administrative, and immunization data.

Is varicella vaccination associated with pediatric arterial ischemic stroke? A population-based cohort study.

Background And Purpose: Varicella disease is a risk factor for pediatric Arterial Ischemic Stroke (AIS). Isolated case reports have emerged suggesting that varicella vaccination may also pose a risk for AIS.

Methods: This retrospective population-based cohort study assessed the risk of AIS in children who received a varicella-containing vaccine, as compared to those who did not.

The effectiveness of shingles vaccine among Albertans aged 50 years or older: A retrospective cohort study.

Purpose: We assessed the effectiveness of shingles vaccine in preventing incident shingles among Alberta residents aged 50 years or older over the period 2009 - 2015, using administrative health data.

Methods: The cohort comprised of Albertans from the Alberta Health Care Insurance Plan Registry (AHCIP) as of June 30, 2009 and aged 50 years or older. Those who received shingles vaccine were identified from the provincial pharmaceutical information network.

How well do ICD-9 physician claim diagnostic codes identify confirmed pertussis cases in Alberta, Canada? A Canadian Immunization Research Network (CIRN) Study.

Background: Rates of Bordetella pertussis have been increasing in Alberta, Canada despite vaccination programs. Waning immunity from existing acellular component vaccines may be contributing to this. Vaccine effectiveness can be estimated using a variety of data sources including diagnostic codes from physician billing claims, public health records, reportable disease and laboratory databases.

Epidemiology of pertussis in Alberta, Canada 2004-2015.

Background: We describe the epidemiology of pertussis in Alberta, Canada by person, place, and time between 2004 and 2015, identify outbreak years, and examine vaccination coverage and vaccination timeliness.

Methods: We used health data from Alberta's Communicable Disease Registry System for the period of January 1, 2004 through August 31, 2015 to identify unique cases of pertussis. Unique cases were deterministically linked to data in Alberta's immunization repository and health care insurance plan registry.

Do children who receive an 'early dose' of MMR vaccine during a measles outbreak return for their regularly scheduled dose? A retrospective population-based study.

Background: Children under the age of 12 months may receive an early dose of measles-mumps-rubella (MMR) vaccine to provide short-term protection in the case of a disease outbreak. Following a measles outbreak in Alberta, Canada, there was concern that children who received an early dose may not be returning for their routinely scheduled dose at 12 months, leaving them vulnerable to disease in the long term.

Methods: This population-based study of children born between 2006 and 2014 used administrative health data to assess coverage and timeliness of the first routine dose of MMR vaccine administered at age 12-24 months for children who received an early dose of the vaccine due to a disease outbreak.

Coverage and Determinants of Uptake for Privately Funded Rotavirus Vaccine in a Canadian Birth Cohort, 2008-2013.

Background: Rotavirus can lead to serious illness or death, even in developed countries. While vaccination can provide protection, many jurisdictions are still grappling with the issue of whether to introduce a universal publicly funded rotavirus vaccination program. This retrospective population-based study assessed rotavirus vaccine coverage, determinants of uptake, and compliance with the recommended schedule in a Canadian jurisdiction with a privately-funded rotavirus vaccination program.

HPV Vaccine utilization, Alberta 2008/09-2013/14 School year.

Background: In Canada both bivalent (bHPV) vaccine and quadrivalent HPV vaccine (qHPV) are authorized for use. In Alberta, while both vaccines are available for private purchase, only qHPV is publicly funded for school girls in grades 5 and 9 as of 2013. We describe HPV vaccine uptake in Alberta, by school year, from the start of the publicly funded program in the Fall of 2008 through to August 31(st) 2014 and estimate the cumulative proportion of the female population who were vaccinated by the end of the 2013/14 school year.

Exploring the heterogeneity among partially vaccinated children in a population-based cohort.

Introduction: Vaccination status is often categorized as complete or not-complete. This ignores the potentially important heterogeneity in children whose vaccinations are not-complete. We sought to subcategorize not-completely vaccinated children and determine whether characteristics differed among these subgroups.

Herpes zoster vaccine (HZV): utilization and coverage 2009 - 2013, Alberta, Canada.

Background: Herpes zoster vaccine (HZV) is not publicly funded in the province of Alberta, Canada. We estimated vaccine coverage among those aged 60 years or older for 2013, as well as vaccine utilization rates per hundred thousand population over the period 2009 - 2013. We explored for factors associated with HZV dispensing rates.

Risk of febrile seizures after first dose of measles-mumps-rubella-varicella vaccine: a population-based cohort study.

Background: The combination measles-mumps-rubella-varicella (MMRV) vaccine currently used in Canada (Priorix-Tetra) may increase the risk of febrile seizures relative to the separate vaccines (MMR and varicella) previously administered. We determined the risk of febrile seizure after the first dose of MMRV, as well as any additional risk for children at high risk for seizures because of pre-existing medical conditions.

Methods: In this retrospective, population-based cohort study, we compared the risk of seizures after the first dose of MMRV with the risk after same-day administration of separate MMR and varicella vaccines (MMR+V) in children 12 to 23 months of age in the province of Alberta.

Shingles in Alberta: before and after publicly funded varicella vaccination.

Purpose: A universal publicly funded chickenpox vaccination program was implemented in Alberta in 2002. We examine the epidemiology of medically attended shingles in Alberta from 1994 to 2010.

Methods: Incident shingles cases (earliest health service utilizations for ICD-9 053 or ICD-10-CA B02) and their co-morbid conditions for the 12 months prior to shingles diagnosis were identified from the records of Alberta's universal, publicly funded health-care insurance system for 1994-2010.