Page 13 of 26
PE18.5 | Immunization in Special Situations — SDL Guide (Part 3)
Self-Assessment
The following cases cover each major special situation category. Work through each independently, applying the five-step framework before checking your reasoning. These scenarios are representative of the type of clinical questions you will encounter in your Paediatrics and Community Medicine postings, as well as in professional examinations. Mastery of these cases reflects genuine readiness to make immunization decisions for complex paediatric patients — not just the ability to recite a list. The five-step framework — identify the situation, classify the vaccine, assess the degree of immunosuppression, decide (proceed/defer/substitute/omit), and document — should be your mental scaffold for each scenario. Apply it deliberately until it becomes automatic, because these decisions have immediate, sometimes life-or-death consequences for real patients in your clinical practice.
- A 3-month-old infant was confirmed HIV-positive at birth by PCR (vertical transmission). She is now on ART and has a CD4 percentage of 22%. She has received BCG and HepB at birth but no other vaccines. Which vaccines from the NIS can be given today, and which must be deferred?
- A 5-year-old child underwent splenectomy 3 weeks ago following blunt abdominal trauma. He received all standard NIS vaccines in infancy but never received PCV or meningococcal vaccine. He is now haematologically stable. What vaccines does he need, and what additional prophylaxis should be considered?
- A 2-month-old infant born at 26 weeks gestation is being discharged from NICU today. Birth weight was 900 g; current weight is 2.1 kg. Chronological age is 8 weeks. What vaccines should she receive today?
- A 12-year-old girl received a high-dose IVIG infusion (2 g/kg) for Kawasaki disease 5 weeks ago. She missed her MR-2 at 18 months and needs it now. Can MR be given today?
- An 8-year-old child is about to start chemotherapy for ALL. She has received all NIS vaccines through 5 years of age (including DPT and MR-2 boosters). What, if anything, should be done regarding immunization before chemotherapy starts?
SELF-CHECK
A 7-year-old child with sickle cell disease has functional asplenia. She has completed all standard NIS vaccines in infancy (DPT, OPV, pentavalent, MR). Which additional vaccines are most important for her, given her asplenic state?
A. Annual influenza vaccine only, as she has completed all other NIS vaccines
B. PCV, meningococcal conjugate vaccine, and annual influenza vaccine
C. Yellow fever and typhoid vaccines
D. Only catch-up doses of any missed NIS vaccines are needed
Reveal Answer
Answer: B. PCV, meningococcal conjugate vaccine, and annual influenza vaccine
Children with functional asplenia (sickle cell disease, surgical asplenia) are at extremely high risk of overwhelming post-splenectomy infection (OPSI) from encapsulated bacteria — primarily Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis. The priority additional vaccines are: PCV (pneumococcal conjugate — if not given in infancy, or booster if primary series was completed), meningococcal conjugate vaccine (MenACWY), and annual inactivated influenza vaccine. Hib conjugate should also be ensured. Yellow fever and typhoid are travel/endemic vaccines, not specifically asplenia-indicated. Completing NIS catch-up alone is insufficient — the encapsulated-organism vaccines above the NIS baseline are what this child particularly needs.