Catch-up immunisation — branching viva · Paeds Vivas

Prompt

Community clinic: newly enrolled preschooler with incomplete and partly overseas vaccination records; parent asks whether to 'start again'.

Stem

You are in clinic with a preschooler and caregiver who ask whether to restart every vaccine. [1]

Examiner: Parent says restart all needles. First response? [1]

Strong answer: Do not restart blindly. Check the national register and written records, count only valid doses, then build an antigen-by-antigen catch-up plan for age. [1] [7]

Examiner: How do you decide a dose is invalid? [1] [3]

Strong answer: Doses before minimum age or before minimum interval usually do not count. Wrong product age band can also invalidate a dose. Same-day inactivated vaccines are generally acceptable. [1] [3]

Examiner: Two live injectables due; only one stocked today. [1]

Strong answer: Give the available live vaccine today with other due inactivated vaccines if appropriate. Book the second live injectable at least 4 weeks later if not same-day. [1]

Examiner: Registry and records empty after a proper search. [1] [4]

Strong answer: After a safety screen, begin age-appropriate catch-up rather than assuming immunity. Give due vaccines today, write the next visit date, and report doses. Do not wait months for a default full serology panel. [1] [4]

Examiner: Measles contact in an under-immunised classmate. [2]

Strong answer: Urgent post-exposure care first, not a routine multi-visit booking. Follow public-health timing for vaccine or immunoglobulin, then complete longer-term catch-up. [2]

Examiner: One system action you will not skip? [7]

Strong answer: Report every dose to the national register so the next clinician inherits a true history. [7]

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

Stem

You are in clinic with a preschooler and caregiver who ask whether to restart every vaccine. [1]

Examiner: Parent says restart all needles. First response? [1]

Strong answer: Do not restart blindly. Check the national register and written records, count only valid doses, then build an antigen-by-antigen catch-up plan for age. [1] [7]

Examiner: How do you decide a dose is invalid? [1] [3]

Examiner: Two live injectables due; only one stocked today. [1]

Strong answer: Give the available live vaccine today with other due inactivated vaccines if appropriate. Book the second live injectable at least 4 weeks later if not same-day. [1]

Examiner: Registry and records empty after a proper search. [1] [4]

Examiner: Measles contact in an under-immunised classmate. [2]

Strong answer: Urgent post-exposure care first, not a routine multi-visit booking. Follow public-health timing for vaccine or immunoglobulin, then complete longer-term catch-up. [2]

Examiner: One system action you will not skip? [7]

Strong answer: Report every dose to the national register so the next clinician inherits a true history. [7]

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