Paeds SAQs · preventive-and-community-paediatrics
Catch-up immunisation and uncertain vaccination history — formative SAQs
Formative SAQs on dose validity, uncertain history and multi-visit catch-up planning.
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Target exams
SAQ 1 (10 marks)
A 3-year-old starts at a new clinic. The parent-held book shows some overseas stamps with unclear dates. The national register is empty. [4] [7]
- Outline how you reconstruct vaccination history at this visit. (3) [1] [7]
- Explain how you decide whether a past dose is valid. (3) [1] [3]
- State your default plan if history remains uncertain and there is no contraindication. (4) [1] [4]
Model answer
Search the national register and local records; take a structured history of countries, clinics, products, ages/dates, and adverse reactions; use interpreters and attempt translation of overseas cards. [1] [7] A dose is valid only if it meets minimum age and minimum interval (and appropriate product age band); too-early or too-soon doses do not count. [1] [3] If uncertainty remains after a real search and the child is safe to vaccinate, begin age-appropriate catch-up rather than assuming immunity or waiting indefinitely for perfect paperwork; give due vaccines today, book the next earliest valid visit, and report doses. [1] [4]
SAQ 2 (10 marks)
A well 12-month-old is due several antigens. Two live injectable vaccines are indicated. The family can only receive one live product today. [1]
- What same-day rule applies if both live injectables can be given? (2) [1]
- If only one is given today, what minimum spacing applies to the second live injectable? (3) [1]
- List three other catch-up principles that reduce visit burden without breaking validity rules. (5) [1] [2]
Model answer
Both live injectable vaccines may be given on the same day. [1] If not given together, separate them by at least 4 weeks. [1] Maximise same-day inactivated vaccines; use age-appropriate combination products; continue from valid prior doses rather than restarting series; book the next earliest valid date before the family leaves; report every dose to the register. [1] [2]
References
- [1]Kroger AT General recommendations on immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR. Recommendations and reports : Morbidity and mortality weekly report. Recommendations and reports, 2006.PMID 17136024
- [2]Issa AN Advisory Committee on Immunization Practices Recommended Immunization Schedule for Children and Adolescents Aged 18 Years or Younger - United States, 2025. MMWR. Morbidity and mortality weekly report, 2025.PMID 39819853
- [3]Stokley S Evaluation of invalid vaccine doses. American journal of preventive medicine, 2004.PMID 14700710
- [4]Abu-Shamsieh A Pediatric Care for Immigrant, Refugee, and Internationally Adopted Children. Pediatric clinics of North America, 2022.PMID 34794672
- [5]Dvergsdal ET Low Childhood Vaccination Coverage among Ukrainian Refugees in Norway. A Nationwide, Register-Based Cohort Study, 2022-2023. Journal of immigrant and minority health, 2025.PMID 40668470
- [6]Schillie S Prevention of Hepatitis B Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices. MMWR. Recommendations and reports : Morbidity and mortality weekly report. Recommendations and reports, 2018.PMID 29939980
- [7]Nyinawingeri A Using the Australian Immunisation Register to support general practices to improve childhood vaccination rates. Australian journal of general practice, 2024.PMID 38437660
- [8]Hull B Annual Immunisation Coverage Report 2023. Communicable diseases intelligence (2018), 2026.PMID 41730159
- [9]Crockett M New faces from faraway places: Immigrant child health in Canada. Paediatrics & child health, 2005.PMID 19668632
- [10]Liang JL Prevention of Pertussis, Tetanus, and Diphtheria with Vaccines in the United States: Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR. Recommendations and reports : Morbidity and mortality weekly report. Recommendations and reports, 2018.PMID 29702631