12.2 Immunization Schedules, Vaccine Selection, and Travel Health
Key Takeaways
- The National Advisory Committee on Immunization issues Canada's evidence-based vaccine recommendations, but each province and territory sets its own publicly funded schedule.
- Live vaccines are contraindicated in pregnancy and in significant immunosuppression, and two live parenteral vaccines must be given on the same day or at least four weeks apart.
- Recombinant zoster vaccine is a two-dose non-live series recommended for adults aged 50 and older, including those who previously had shingles or received the live vaccine.
- Anaphylaxis to a previous dose or to a vaccine component is a true contraindication; a minor illness, a low-grade fever, or a family history of reaction is not.
- Travel consultations should occur at least six weeks before departure, and yellow fever vaccine is only available from designated yellow fever vaccination centres.
12.2 Immunization Schedules, Vaccine Selection, and Travel Health
Exam Focus: The syllabus names "current childhood immunization schedules and vaccine administration issues in children" under special populations, and immunization appears again under health promotion. Expect contraindication screening, interval rules, and travel risk assessment.
How Canadian Immunization Is Governed
The National Advisory Committee on Immunization (NACI) provides Health Canada with independent, evidence-based recommendations, published in the Canadian Immunization Guide. NACI advises; it does not fund. Each province and territory decides which vaccines are publicly funded, for whom, and on what schedule. A vaccine can therefore be NACI-recommended and still be purchased privately in one province while free in another. Always confirm both the clinical recommendation and the local funding rule before advising a patient about cost.
Routine Childhood Immunization
Provincial schedules differ in detail but share a common architecture:
| Age | Typical antigens |
|---|---|
| 2, 4, 6 months | Diphtheria, tetanus, acellular pertussis, polio, Haemophilus influenzae type b (as a combined product); pneumococcal conjugate; rotavirus (oral); meningococcal C in some provinces |
| 12 to 18 months | Measles, mumps, rubella; varicella; pneumococcal conjugate booster; meningococcal C |
| 4 to 6 years | Diphtheria, tetanus, pertussis, polio booster; second measles-mumps-rubella or measles-mumps-rubella-varicella |
| Grade 4 to 7 (school programs) | Hepatitis B; human papillomavirus; meningococcal quadrivalent |
| 14 to 16 years | Tetanus, diphtheria, pertussis booster |
Rotavirus vaccine is oral and live, and the first dose has an upper age limit because of intussusception risk, so late starts cannot simply be caught up.
Adults should receive a tetanus-diphtheria booster every 10 years with one adult dose containing pertussis, annual influenza vaccine from 6 months of age onward, COVID-19 vaccine as recommended each season, recombinant zoster vaccine as two doses from age 50, and pneumococcal vaccination as recommended for age and risk. Pregnant patients should receive influenza vaccine in any trimester and a pertussis-containing vaccine in every pregnancy to provide passive protection to the newborn.
Contraindications, Precautions, and False Contraindications
| True contraindication | Applies to |
|---|---|
| Anaphylaxis to a previous dose or a vaccine component | That vaccine |
| Pregnancy | Live vaccines (measles-mumps-rubella, varicella, live attenuated influenza, yellow fever with limited exceptions) |
| Significant immunosuppression | Live vaccines |
| Encephalopathy within 7 days of a pertussis-containing vaccine | Further pertussis-containing vaccines |
Precautions (defer, weigh, or take extra care) include moderate to severe acute illness with fever, a history of Guillain-Barré syndrome within 6 weeks of a prior tetanus or influenza vaccine, and recent receipt of blood products, which can blunt the response to measles-containing and varicella vaccines.
False contraindications — these are not reasons to withhold a vaccine: mild illness with or without low-grade fever, current antibiotic therapy, prematurity, breastfeeding, a family history of adverse events, non-anaphylactic egg allergy for influenza vaccine, a prior local reaction, and stable neurological conditions.
Interval rules: inactivated vaccines may be given at any interval relative to each other and to live vaccines. Two live parenteral vaccines must be given on the same day or separated by at least four weeks, because the immune response to the first can blunt the second.
Catch-Up and Documentation
For a patient with an incomplete or missing record, the principle is "the series does not restart" — resume from where it stopped, using minimum intervals rather than routine intervals to complete it efficiently. Verify records from the provincial registry, the previous provider, or the patient's own card. Undocumented vaccination is treated as not given, though serology is an option for some antigens such as hepatitis B and measles. Record every administration with the product, lot number, expiry, dose, site, route, date, and administrator, and report it to the provincial registry where required.
The Travel Health Consultation
Ideally conducted at least six weeks before departure, allowing time for multi-dose series and for immunity to develop.
Assess: exact destinations including rural or urban, dates and duration, style of travel and accommodation, planned activities such as trekking or animal contact, altitude, health status and pregnancy, current medications, and immunization history.
| Category | Examples |
|---|---|
| Routine to update | Measles-mumps-rubella, tetanus-diphtheria-pertussis, polio, influenza, COVID-19 |
| Commonly recommended | Hepatitis A, hepatitis B, typhoid |
| Destination-specific | Yellow fever, Japanese encephalitis, rabies pre-exposure, meningococcal quadrivalent |
| Required for entry | Yellow fever for certain countries; meningococcal for Hajj pilgrimage |
Yellow fever vaccine may only be administered at a designated yellow fever vaccination centre, which issues the International Certificate of Vaccination or Prophylaxis; the certificate becomes valid 10 days after vaccination.
Malaria prevention
Prevention rests first on bite avoidance: an insect repellent containing DEET or icaridin, permethrin-treated clothing, insecticide-treated bed nets, and covering skin at dusk and dawn.
| Agent | Dosing | Key points |
|---|---|---|
| Atovaquone-proguanil | Daily; start 1 to 2 days before, continue 7 days after leaving | Well tolerated; take with food or a milky drink |
| Doxycycline | Daily; start 1 to 2 days before, continue 4 weeks after | Photosensitivity, esophagitis — take upright with water; avoid in pregnancy and in children under 8 |
| Mefloquine | Weekly; start 2 to 3 weeks before, continue 4 weeks after | Avoid with a history of psychiatric or seizure disorder |
| Chloroquine | Weekly | Only for the few remaining chloroquine-sensitive areas |
Emphasise that no prophylaxis is fully protective, and that any fever during travel or within a year of return must be assessed urgently for malaria.
Traveller's diarrhea and other advice
Advise safe food and water practices, and provide oral rehydration salts. Loperamide is appropriate for mild non-bloody diarrhea without fever. Standby antibiotic therapy may be supplied for moderate to severe illness, chosen with local resistance in mind; azithromycin is preferred in South and Southeast Asia because of fluoroquinolone resistance. Counsel additionally on venous thromboembolism prevention on long flights, altitude illness where relevant, sun protection, and the practical rule of carrying medicines in hand luggage in original labelled containers with a copy of the prescription.
A 62-year-old asks about shingles vaccination. She had shingles four years ago and received the older live zoster vaccine in 2015. What is the appropriate advice?
Which of the following is a true contraindication to measles-mumps-rubella vaccination?
A patient received varicella vaccine 10 days ago and now needs measles-mumps-rubella vaccine. What is the correct interval advice?
A traveller leaving for rural Ghana in five weeks needs malaria prophylaxis. She is 10 weeks pregnant. Which agent is inappropriate?