Which of the following vaccines is freeze-sensitive and must NOT be stored or transported below 0 degrees Celsius, as freezing causes irreversible loss of potency due to adjuvant aggregation?

• A Oral Polio Vaccine (OPV)
• B DPT (Diphtheria-Pertussis-Tetanus) vaccine ✓
• C Measles / Measles-Rubella vaccine
• D BCG vaccine

Explanation

DPT is an alum-adsorbed vaccine and is freeze-sensitive. Freezing disrupts the alum adjuvant, causing clumping and irreversible loss of immunogenicity. OPV, measles, and BCG are live vaccines that are heat-sensitive (not freeze-sensitive) and are stored at -20 degrees Celsius at the national and state levels, though at the PHC level they are kept in the ILR at +2 to +8 degrees Celsius for short-term use.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.