Potential strategies to improve childhood immunization rates in Canada

The Canadian Paediatric Society gives permission to print single copies of this document from our website. For permission to reprint or reproduce multiple copies, please see our copyright policy.

From a population perspective, the health benefits of the childhood vaccines being offered routinely in Canada are overwhelming compared with potential side effects ^[1]. Yet many children are underimmunized. Common reasons for this problem include parents simply forgetting that their child is due for an immunization, having difficulty getting to a clinic during regular hours, being unconvinced that vaccine-preventable diseases pose a real threat, believing that children are ‘too young’ for certain vaccines (or that they are receiving too many vaccines or that they should develop ‘natural immunity’), and, finally, having concerns about the trustworthiness of health care workers or the safety and efficacy of vaccines ^[2].

Recent outbreaks of measles and a growing public recognition that measles will spread unless approximately 95% of the general population is immune have raised interest in using school entry requirements to increase immunization uptake and prevent spread of vaccine-preventable diseases. It is better appreciated now that even if the national target of 95% were achieved, outbreaks could still occur in communities where a large number of people are unvaccinated ^[3]. In Ontario and New Brunswick and throughout the United States and Australia, it has long been required that children be fully immunized before they can enter school.

Immunization uptake rates in Canada can only be estimated because regional registries are relatively new and vaccines can be obtained from multiple providers. Coverage rates are assessed by Childhood National Immunization Coverage Surveys (CNICS), which are conducted by Statistics Canada every 2 years ^[4]. The most recent data reported are from March 1, 2021. For 2-year-old children, coverage for individual vaccines were estimated as follows: measles, mumps, and rubella (MMR, at least one dose) at 92%, varicella vaccine 88%, diphtheria, tetanus, and pertussis (DTaP) 77%, poliovirus vaccine 92%, Haemophilus influenzae type B (Hib vaccine) 75%, meningococcal disease vaccine 91%, pneumococcal disease 85%, and rotavirus vaccine 86%. For 7-year-old children, coverage for the tetanus, diphtheria, pertussis booster (TdaP) was 72%. For 14-year-olds, coverage for human papillomavirus (HPV) vaccine was 84% and hepatitis B virus (HBV) vaccine 89%. For 17-year-olds, 93% had TdaP boosters and 89% received meningococcal vaccine ^[4].

Immunization rates in 2021 were similar to those of 2019 except for an increase in HPV vaccination for boys, but none met Canada’s national vaccine coverage goals. Rates varied significantly among provinces and territories ^[4][5].

Similar trends were noted in the US and Australia. In 2021-22, vaccination coverage rates in kindergartens in the US were 93.5% (for 2 doses of MMR; 93.1% for the state-required number of DTaP doses; 93.5% for polio vaccine; and 92.8% for state-required varicella vaccine doses ^[6]. A follow-up survey in 2022-23 showed that while national coverage remained around 93%, the coverage rates for these  vaccines in 12 to 14 states were <90% ^[7]. During 2022, adolescent coverage rates were 76%, 88.6%, and 89.9% for ≥1 dose of HPV vaccine, ≥1 dose of meningococcal (MenACWY) vaccine, and ≥1 Tdap dose ^[8]. In Australia, the national coverage rates were 93.2%, 91.2%, and 93.9% in all 1-year-olds, 2-year olds, and 5-year olds respectively, as of December 2023 ^[9].

Because the decision to immunize is complex for many parents, new Canadian immunization strategies need to be carefully considered and implemented. One disadvantage of changing school entry requirements is that even parents who support immunization might see this approach as impinging on their right to choose what they consider to be best for their child. School entry requirements could thus, inadvertently, feed into rights-based objections in anti-immunization campaigns, both in print and across social media. This problem is partially anticipated by allowing nonmedical exemptions, but recent reviews have also reported rising rates of requests for nonmedical exemptions both in the US ^[10] and Ontario ^[3], ultimately defeating the purpose of revising school entry requirements. Previous CNICs showed that uptake rates in Ontario and New Brunswick, the two provinces with school entry requirements, were similar to other jurisdictions [11,12].

While school entry requirements in the US increased uptake ^[13] initially and significantly, they were introduced decades ago, at a time when societal responsibilities still outweighed individual rights. This balance may not exist in Canada today. One recent systematic review found that studies to support school entry requirements were primarily from jurisdictions with relatively low baseline immunization rates ^[14]. Also, negative publicity surrounding school entry requirements might cause parents who would otherwise have immunized their children on time to delay until school entry. There is some evidence that such delays are occurring more often in the US ^[15]. Because many vaccine-preventable infections are most severe in young children, this trend is concerning. Parents could also ‘bypass’ mandates by home-schooling their children. Substantial economic and legislative resources are required to enforce school entry requirements.

Financial incentives to encourage parents to immunize their children have been instituted in Australia, with no allowance for nonmedical exemptions ^[16]. These programs and outcomes are yet to be studied. It would be difficult to initiate financial incentives in Canada, as the patchwork of registries makes it difficult to verify each child’s immunization status.

Canadian health policy must aim to ensure that parents immunize their children for positive reasons: to protect against disease and minimize risk, rather than to avoid legal repercussions associated with nonvaccination ^[17].

RECOMMENDATIONS TO IMPROVE IMMUNIZATION UPTAKE

The following recommendations are primarily based on expert opinion as most studies do not reflect the current Canadian context.

1. Provinces and territories should be required to establish electronic immunization registries, with online records for all children being readily accessible to health care providers. Having current, searchable databases would improve data collection and tracking.
2. Parents should be notified automatically when their child is overdue for an immunization. Text messages with e-mail follow-up are probably the most effective reminders for young parents, who tend to change their home addresses frequently. Online registries and transferrable immunization records would help to expedite this process.
3. Public health clinics and all vaccine providers should promote the CANimmunize app (www.canimmunize.ca) to help parents to keep track of immunizations.
4. Address barriers to equitable access: Clinic or health centre hours and locations should be convenient for working parents. In every community, there should be at least one ‘walk-in’ clinic offering immunizations on certain days without appointment. When appointments are scheduled, the process should be simple and linguistically inclusive. Wait times should be no longer than 2 weeks from the date of request. In regions where immunizations are usually delivered by physicians, family medicine walk-in clinics should be required to provide all routine vaccines.
5. Providing accurate immunization records should be mandatory for school entry. Such records are invaluable for public health authorities when outbreaks occur.
6. To serve children whose parents may be noncompliant but not opposed to immunization, a school-based immunization program should be provided at least once during each school year. Parents of children who do not return consent forms should be contacted individually. Vaccine-hesitant parents should be guided to appropriate resources, ideally a short local course offered at the school or online.
7. Canadian school curriculums should include education on vaccine-preventable diseases and the benefits of vaccines, such that the next generation of parents better understands disease risks, vaccine effects and the importance of community immunity.

Further research is needed on health outcomes and cost-effectiveness related to new or newly enforced immunization requirements at child care or school entry, financial incentive programs and other potential strategies to increase vaccine uptake.

Addendum

The COVID-19 pandemic clarified the many and complex factors contributing to lower vaccine uptake in Canada generally and within marginalized groups in particular. Strategies to improve immunization rates must be tailored for various populations based on betterunderstanding of existing inequities and factors compounding distrust of the health care system—and providers—that can affect vaccine uptake. Such strategies require innovative, multifaceted, non-prescriptive approaches that engage affected communities and are predicated on an understanding that suboptimal vaccine coverage is multifactorial. Low uptake is not caused by vaccine hesitancy alone, but is often influenced by problems of access. Creative strategies and programs are needed to expand vaccine access to immigrant families and other populations experiencing barriers to obtaining routine childhood immunizations. ALL children and youth should have equal access to primary care, including vaccines, to optimize both individual and population-based disease prevention in Canada.

Acknowledgements

This statement was reviewed by the Community Paediatrics Committee of the Canadian Paediatric Society and representatives from the College of Family Physicians of Canada

CPS INFECTIOUS DISEASES AND IMMUNIZATION COMMITTEE (2018)

Members: Michelle Barton-Forbes MD; Natalie A. Bridger MD; Shalini Desai MD; Michael Forrester MD; Ruth Grimes MD (Board Representative); Charles Hui (past member); Nicole Le Saux MD (Chair); Marina I. Salvadori MD (past member); Otto G. Vanderkooi MD

Liaisons: Upton D. Allen MBBS, Canadian Pediatric AIDS Research Group; Tobey Audcent MD, Committee to Advise on Tropical Medicine and Travel (CATMAT), Public Health Agency of Canada; Carrie Byington MD, Committee on Infectious Diseases, American Academy of Pediatrics; Fahamia Koudra MD, College of Family Physicians of Canada; Rhonda Kropp BScN MPH, Public Health Agency of Canada; Marc Lebel MD, IMPACT (Immunization Monitoring Program, ACTIVE); Jane McDonald MD, Association of Medical Microbiology and Infectious Disease Canada; Dorothy L. Moore MD, National Advisory Committee on Immunization (NACI)

Consultant: Noni E. MacDonald MD

Principal author: Joan L. Robinson MD

Updated in July 2024 by: Michelle Barton MD, Dorothy Moore L. MD, Cora Constantinescu MD

References

Disclaimer: The recommendations in this position statement do not indicate an exclusive course of treatment or procedure to be followed. Variations, taking into account individual circumstances, may be appropriate. Internet addresses are current at time of publication.