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PE18.1-14 | Immunization — Graded Quiz
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A health worker is about to administer BCG to a newborn. She notes the BCG vial was stored in the deep freezer at −20°C. After reconstitution, she has 1.5 mL remaining after giving 3 doses. What is the maximum time limit for using the remaining reconstituted BCG?
Reconstituted BCG must be used within 3 hours of reconstitution due to rapid degradation of the live attenuated bacilli at room temperature. Unused vaccine after 3 hours must be discarded. This is shorter than OPV (use same session) and MMR (1 hour at room temperature).
Post-reconstitution stability: BCG = 3 hours; MMR = 1 hour; OPV = use during session (return to freezer if MDV policy applies). Multi-dose vials opened policy: discard at end of session for most vaccines; BCG within 3 hours regardless.
BCG reconstituted vaccine has a 3-hour window, not 6 or 24 hours. Keeping it in the cold box does not extend this window because the live bacilli in the liquid state are inherently unstable.
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During a measles eradication campaign, a AEFI surveillance officer receives a report of a 2-year-old child who developed fever >40°C and febrile seizure 6 hours after receiving MR vaccine. This is best classified as which type of AEFI that requires urgent investigation?
A febrile seizure is a serious AEFI (requires hospitalization or is life-threatening). Serious AEFIs must be reported within 24 hours to the district/block AEFI committee, and a causality assessment must be conducted. The event should then be classified by cause (product-related, error-related, coincidental, or anxiety-related).
Serious AEFI criteria: hospitalization or prolongation of existing hospitalization; life-threatening; death; persistent/significant disability; congenital anomaly. Report time: <24 hours for serious AEFI. Causality assessment follows Brighton Collaboration criteria.
A seizure is never a non-serious AEFI. Without investigation, one cannot call it coincidental. No programmatic error has been described in the stem.
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A community health worker visits a household where a 9-month-old child has not received any vaccines due to parental refusal. The mother states she 'does not believe in vaccines.' After appropriate education and counselling, the mother agrees. The health worker administers MR-1 and OPV-3 at the same visit. Regarding informed/implied consent, which statement is correct?
In immunization practice, implied consent is the standard: a parent who brings a child to the immunization clinic and presents them for vaccination implies consent. After verbal counselling and the parent's agreement (nodding/presenting the child), vaccination can proceed without a formal written consent form in routine UIP practice. Written consent is needed for specific research or clinical trial contexts.
Implied consent in immunization: the act of bringing the child to the vaccination site and presenting them after counselling constitutes implied consent. Health workers must still explain benefits, risks, and AEFI before proceeding. Documentation of verbal consent in registers is good practice.
Indian law does not mandate written consent for routine UIP vaccines. Public health mandates do not override consent — immunization in India is not compulsory. Implied consent through attendance + verbal agreement is universally accepted in routine immunization.
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A 5-year-old child is due for his DPT booster and OPV booster at 5–6 years under the NIS. His mother reports he had severe anaphylaxis after the first dose of DPT (at 6 weeks). Which is the most appropriate management?
Anaphylaxis after DPT is an absolute contraindication to further whole-cell DPT. The pertussis component is most commonly implicated. The child should be evaluated by an allergist/immunologist; acellular pertussis (DTaP) or DT (without pertussis) may be given depending on the implicated component. This is the standard WHO/IAP recommendation.
Absolute contraindications to DPT: anaphylaxis to a prior dose; encephalopathy within 7 days of a prior dose. Precautions: fever >40.5°C within 48h; hypotonic-hyporesponsive episode; persistent inconsolable crying >3 hours within 48h. In these cases, use DT (without pertussis) or acellular DTaP.
Re-challenging with the same DPT after prior anaphylaxis risks a fatal reaction. Half-dose intradermal DPT has no safety evidence and is not a recognized approach. Withholding all immunization denies protection against diphtheria and tetanus.
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A medical officer at a PHC discovers that the deep freezer has malfunctioned and OPV vials stored at −20°C have risen to +10°C over 12 hours. A shake test is performed on OPV. What is the expected result of the shake test, and what action should be taken?
The shake test is ONLY applicable to freeze-sensitive adsorbed vaccines (DPT, pentavalent, Hep B, TT, Td, IPV) to detect freezing damage. OPV is a liquid live vaccine — it does not contain aluminum hydroxide adjuvant and therefore does not form a flocculate. For OPV, use the VVM: if Stage 1 or 2 after heat exposure, it can be re-stored and used. OPV exposed to heat that remains VVM-positive may be reused.
Shake test: applicable ONLY to adjuvanted (adsorbed) vaccines — DPT, pentavalent, Hep B, Td, TT, IPV. Method: vigorously shake both suspect and control vials; allow to stand for 30 minutes; if suspect shows sediment that doesn't redisperse while control clears, the vaccine has been freeze-damaged. OPV, BCG, MMR, rotavirus, and yellow fever: assess by VVM only.
The shake test cannot be applied to OPV because OPV is a liquid without adjuvant. Flocculate formation is specific to adsorbed vaccines. OPV heat exposure is evaluated by VVM.
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A 10-year-old boy with sickle cell disease (functional asplenia) needs vaccination guidance. Which additional vaccine is specifically recommended for him beyond the routine NIS schedule?
Functional asplenia (sickle cell disease, post-splenectomy) greatly increases risk from encapsulated bacteria — Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae type b. PCV13/PCV15 and meningococcal vaccine (MenACWY) are specifically recommended, along with annual influenza vaccine.
Asplenic/hyposplenic children need: PCV (pneumococcal conjugate), meningococcal conjugate (MenACWY), Hib (if not previously vaccinated), and annual influenza vaccine. Prophylactic penicillin is also recommended. Vaccines should ideally be given ≥2 weeks before planned splenectomy.
OPV booster is not specifically indicated for asplenia. Rotavirus is for infants under 8 months. BCG re-vaccination is not recommended in India as a routine measure.
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A parent refuses the oral rotavirus vaccine for her 6-week-old, citing fears that it contains a pig-derived component and conflicts with her religious beliefs. As the immunizing physician, what is the ethically and medically correct approach?
The ethical approach is to provide accurate, evidence-based information — including the disease burden of rotavirus diarrhoea (leading cause of severe diarrhoea mortality in Indian children under 5) and the safety profile — and then respect the autonomous decision of the parent if she still refuses after full counselling. Vaccination is not compulsory in India; implied consent can be withheld.
Vaccine counselling should address: disease burden, vaccine composition/safety, common AEFIs, and the schedule. Document informed refusal. Cultural and religious concerns must be addressed respectfully. India's immunization programme is voluntary.
Administering a vaccine without consent is assault. Threatening reporting to authorities is coercive and unethical. No inactivated parenteral rotavirus vaccine is licensed in India.
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A 7-year-old child is travelling to a country with active yellow fever transmission. He is asymptomatic HIV-positive with a CD4 count of 22% (normal for age). Which statement about yellow fever vaccination is correct?
WHO and CDC guidance: yellow fever vaccine may be considered in HIV-positive persons with CD4 ≥15% (children) or CD4 ≥200 cells/mm³ (adults) after weighing individual risk of exposure against vaccine risk. CD4 22% is above the 15% threshold, making consideration appropriate with expert consultation. Travel avoidance is preferable, but if travel is unavoidable, vaccination with monitoring is an option.
Yellow fever vaccine (live attenuated): contraindicated in severe HIV immunosuppression (CD4 <200/mm³ in adults or <15% in children), symptomatic HIV, or any severe combined immunodeficiency. In asymptomatic HIV with CD4 ≥15% and unavoidable travel to endemic areas, the vaccine may be offered after expert consultation.
The absolute contraindication is CD4 <15% (severe immunosuppression) or symptomatic HIV. At CD4 22%, the vaccine is not absolutely contraindicated. Symptomatic status alone is not sufficient — CD4 threshold matters. Avoiding travel is ideal but sometimes not feasible.
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The Vaccine Cold Chain requires vaccines to be maintained at specific temperatures at each level. Which cold chain equipment is used at the district vaccine store to maintain vaccines at +2°C to +8°C?
The Ice-Lined Refrigerator (ILR) maintains vaccines at +2°C to +8°C. It has an inner ice lining that maintains temperature during power cuts for up to 12–16 hours. ILRs are used at PHC, CHC, and district levels for all vaccine storage.
Cold chain hierarchy: National/Regional store → Deep Freezer (−15 to −25°C); District/PHC → ILR (+2 to +8°C); Transport → Cold Box; Outreach → Vaccine Carrier. Freeze-sensitive vaccines (DPT, pentavalent, Hep B, Td, IPV) must NEVER reach below 0°C. OPV is stored in deep freezers and moved to ILR on the day of use.
Deep freezers maintain −15 to −25°C and are used for OPV, varicella, and other freeze-tolerant vaccines. Cold boxes are passive storage for vaccine transport. Vaccine carriers are used for last-mile delivery to outreach sessions.
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A final-year medical student is to demonstrate the correct technique for administering the 6-week Pentavalent vaccine. Which site and route is correct?
Pentavalent vaccine is given IM into the anterolateral aspect of the mid-thigh in infants. The thigh provides a large muscle mass with less risk of neurovascular injury compared to the deltoid in infants. Dose is 0.5 mL. The right deltoid is used for BCG (ID) and later vaccines when deltoid muscle is adequate (after 1 year).
Vaccine administration sites: BCG = right upper arm/deltoid, ID, 0.05 mL (neonates) / 0.1 mL (>1yr); OPV = oral, 2 drops; Pentavalent/DPT/Hep B = anterolateral thigh IM, 0.5 mL (infants); MR/MMR = subcutaneous, 0.5 mL; fIPV = anterolateral thigh, ID, 0.1 mL. Always aspirate is NOT required for IM vaccines per WHO guidelines.
Right deltoid IM is appropriate for older children/adults, not infants under 1 year. BCG uses the right upper arm intradermally (0.05 mL). Pentavalent is NOT given subcutaneously — IM is required for proper immune response and reduced local reactions.
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