Vaccine Storage in the Cold Chain
In the Universal Immunization Programme (UIP) cold chain, refrigerator space is divided by each vaccine's sensitivity to heat and freezing. Freeze-sensitive, heat-stable live attenuated vaccines are kept on the top rack of the ILR/refrigerator, while heat-sensitive vaccines are kept lower down, closer to the cooling source, and diluents are kept in the door.
Why BCG, Measles and MMR (Option B) is Correct
- BCG: A live attenuated vaccine that is relatively heat-stable but must never be frozen. It is stored on the top rack at 4–10°C (within the broader 2–8°C cold chain range), away from the direct cold of the freezer compartment/evaporator plate.
- Measles vaccine: Also a live attenuated, freeze-tolerant-but-heat-sensitive lyophilized vaccine; it is one of the most heat-labile vaccines and is conventionally shelved on the top rack, farthest from the door, to keep it consistently cool.
- MMR: Similarly a live, lyophilized vaccine with the same top-rack storage requirement as measles vaccine.
These three share the property of being live, freeze-labile, and needing the coolest but non-freezing zone of the refrigerator - hence their placement together on the top rack.
Why the Other Options Are Wrong
- DPT, Hepatitis B, Measles, MMR vaccines: Incorrect because DPT and Hepatitis B are adsorbed/inactivated vaccines that are highly freeze-sensitive (freezing destroys the adjuvant and denatures the antigen). These are stored on the middle rack, not the top rack, to keep them further from any freezing risk near the top of the compartment in some ILR designs, and by convention are grouped separately from the live vaccines.
- BCG, DPT and Typhoid: Incorrect because DPT does not belong with the top-rack live vaccines (see above), and Typhoid vaccine (polysaccharide/conjugate) is also not part of this top-rack live-vaccine group.
- DPT, TT, Hepatitis A vaccine: Incorrect because DPT, TT (Tetanus Toxoid), and Hepatitis A are all inactivated/toxoid vaccines that are freeze-sensitive and are conventionally stored on the middle rack (2-8°C, away from the coldest zone), not the top rack.
Conclusion
The correct answer is BCG, Measles and MMR vaccines, as these are the live, freeze-labile vaccines conventionally stored on the top rack of the refrigerator.
Important Questions from Child Immunization
Which of the following are correct with regard to BCG vaccination?
1. It is a live-attenuated vaccine.
2. It is administered by intramuscular injection.
3. It is derived from Mycobacterium bovis.
4. It is highly immunogenic.
Select the answer using the code given below :
Consider the following statements :
1. Hepatitis B vaccine has reduced efficacy, if administered intramuscularly.
2. The maximum time allowed between reconstitution of MMR vaccine and use is 30 minutes.
3. Maternal antibodies do not interfere with cellular immune response to BCG vaccine.
4. DTwP is preferred to DTaP for primary immunization in most children.
Which of the statements given above are correct?
- Rotavirus vaccination is avoided during an episode of diarrhoea because
- The event related to vaccination which can be contraindication for the next vaccination of similar/identical type is
Which of the following events could be caused or precipitated by an active component of vaccine?
1. Anaphylaxis after measles vaccine
2. Encephalopathy after DPT vaccine
3. Adenitis following BCG vaccine
4. Gastroenteritis following MMR vaccine
Select the correct answer using the code given below.
