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

DPT belongs to the group of liquid, aluminium adjuvant vaccines, and this group behaves very differently from live vaccines when it comes to cold chain rules, which is the key idea behind this question.

1. It should be stored in deep freezer: This is wrong. DPT is freeze sensitive because it carries an aluminium adjuvant, and freezing breaks that adjuvant apart, so putting it in a deep freezer ruins the vaccine instead of protecting it.
2. Exposure to direct sunlight when in use should be avoided: This is correct, since heat and light both reduce the potency of the vaccine once the vial is opened for a session.
3. Store stocks are needed for three months at PHC level: This matches the standard cold chain planning used in the Indian immunization programme, where each level keeps a set reserve of stock, and three months is the accepted figure at the primary health centre.
4. Half used vials should not be put back into the cold chain after the session: This is correct as classically taught, since an opened multi dose vial carried back and forth risks contamination, so it should be discarded rather than reused in a later session.

Three of these four statements describe DPT handling correctly. Only the deep freezer claim is wrong, because freezing is exactly what damages this vaccine.

Let's summarize:

• DPT is freeze sensitive, store it at 2 to 8 degrees Celsius in the fridge body, never in the freezer.
• Protect it from sunlight during use, follow the stock duration norms, and discard opened vials after a session.

So the exception, the statement that is not true, is that DPT should be stored in a deep freezer.