Question

All of the following statements are true about DPT vaccine except:

• A. It should be stored in deep freezer
• B. Exposure to direct sunlight when in use should be avoided
• C. Store stocks are needed for three months at PHC level
• D. Half used vials should not be put back into the cold chain after the session

Hint:

DPT is a freeze sensitive, adjuvant containing vaccine, it must stay refrigerated at 2 to 8 degrees Celsius and never be frozen.

Answer 1

The Correct Option is A

Step 1: Understanding the Question.
This is an except question about how the DPT vaccine should be stored and handled in the cold chain, and we need to find the one statement that is not correct.

Step 2: Key Concept or Approach.
Vaccines are grouped by how they react to heat and cold. Live vaccines like OPV, BCG, and measles tolerate freezing and are kept in the freezer compartment or ice packs. Liquid adsorbed vaccines that contain an aluminium adjuvant, such as DPT, DT, TT, and hepatitis B, are freeze sensitive, freezing wrecks the adjuvant and ruins the vaccine, so these must be kept in the body of the refrigerator between 2 and 8 degrees Celsius and never allowed to freeze.

Step 3: Detailed Explanation.
DPT is one of these freeze sensitive, adsorbed vaccines, so storing it in a deep freezer is wrong and would destroy the vaccine, which makes option 1 the false statement. Direct sunlight and heat degrade the potency of DPT during a session, so avoiding sun exposure while the vial is in use, as stated in option 2, is correct practice. Vaccine stock is held for different durations at different levels of the cold chain, with smaller working stocks near the top of the chain and larger reserve stocks lower down, and a three month store at the primary health centre level, as in option 3, matches standard Indian immunization programme guidance. Once a multi dose vial of DPT has been opened and used in a session, it should not be carried back into the cold chain and reused later, since repeated temperature changes and handling raise the risk of contamination, so option 4 is correct as taught.

Step 4: Final Answer.
The false statement is that DPT should be stored in a deep freezer, since DPT is a freeze sensitive vaccine that must be kept refrigerated, not frozen.