Impact of vaccine delays at the 2, 4, 6 and 12 month visits on incomplete vaccination status by 24 months of age in Quebec, Canada

Abstract

BackgroundTimeliness in the administration of recommended vaccines is often evaluated using vaccine delays and provides more information regarding the susceptibility of children to vaccine-preventable diseases compared with vaccine coverage at a given age. The importance of on-time administration of vaccines scheduled at the first visit is well documented, but data are scarce about the impact of vaccine delays at other visits on vaccination status by 24 months of age. Using vaccine delays for the first three doses of DTaP-containing vaccines and for the first dose of measles-containing vaccines as markers of timeliness at the 2, 4, 6 and 12 month visits, we estimated the proportion of incomplete vaccination status by 24 months of age attributable to a vaccine delay at each of these visits.MethodsWe used the data from six cross-sectional coverage surveys conducted in the Province of Quebec from 2006 to 2016 which included 7183 children randomly selected from the universal health insurance database. A vaccine dose was considered delayed if received 30 days or more after the recommended age. The impact of new vaccine delays at each visit on incomplete vaccination status by 24 months of age was estimated with the attributable risk in the population.ResultsThe proportion of children with vaccine delay was 5.4% at 2 months, 13.3% at 4 months, 23.1% at 6 months and 23.6% at 12 months. Overall, 72.5% of all 2-year-old children with an incomplete status by 24 months were attributable with a vaccine delay, of which 16.1% were attributable with a first vaccine delay at 2 months, 10.6% at 4 months, 14.0% at 6 months and 31.8% at 12 months.ConclusionsWhile great emphasis has been put on vaccine delays at the first vaccination visit, the prevalence of vaccine delays was greater with later visits and most children with an incomplete vaccination status by 24 months had a vaccine delay occurring during these later visits. Interventions to improve timeliness should address vaccine delays at each visit and not only focus on the first visit.Electronic supplementary materialThe online version of this article (10.1186/s12889-018-6235-6) contains supplementary material, which is available to authorized users.

Timely completion of vaccination and its determinants among children in northwest, Ethiopia: a multilevel analysis

“…In terms of control and prevention of childhood infectious diseases, achieving high vaccination coverage is a necessary; but insufficient indicator to assess the success of immunization program. In order to successfully control and eliminate vaccine-preventable infectious diseases, age appropriate vaccine coverage has to be achieved and maintained [9][10][11][12].…”

Vaccine hesitancy among parents of preschoolers in Canada: a systematic literature review

“…This survey is stratified to represent the Canadian population but excludes children living on First Nation reserves and institutionalized children (Statistics Canada 2019). Three studies sampled provincial birth cohorts using medical records and socio-demographic data (Bell et al 2015) or a combination of medical records, parental vaccine records, and surveys (Dummer et al 2012;Kiely et al 2018). However, Bell et al (2015) excluded babies living on First Nation reserves in Alberta and Kiely et al (2018) excluded data from the two northern regions in Quebec.…”

“…Three studies sampled provincial birth cohorts using medical records and socio-demographic data (Bell et al 2015) or a combination of medical records, parental vaccine records, and surveys (Dummer et al 2012;Kiely et al 2018). However, Bell et al (2015) excluded babies living on First Nation reserves in Alberta and Kiely et al (2018) excluded data from the two northern regions in Quebec. One study used medical records and a parental survey data from Edmonton (MacDonald et al 2014) and another used medical records and sociodemographic data from Winnipeg (Martens et al 2014).…”

“…Studies used various indicators to assess vaccine status. Studies whose samples were within one province assessed vaccine status according to the provincial recommendations (Bell et al 2015;Dubé et al 2016c;Dummer et al 2012;Kiely et al 2018;Kuwaik et al 2014;MacDonald et al 2014;Martens et al 2014;O'Donnell et al 2017). Studies using national-level data assessed vaccine status using specific vaccines that are routinely provided across Canada (i.e., measles or MMR) (Greenberg et al 2017;Perinet et al 2018) or a combination of measles and pertussis vaccines (Carpiano et al 2019;Gilbert et al 2017).…”

Timely completion of vaccination and its determinants among children in Northwest, Ethiopia: A multilevel analysis

“…In terms of control and prevention of childhood infectious diseases, achieving high vaccination coverage is a necessary; but insufficient indicator to assess the success of immunization program. In order to successfully control and eliminate vaccine-preventable infectious diseases, age appropriate vaccine coverage has to be achieved and maintained (9)(10)(11)(12).…”