After a suspected overnight power failure, a cold chain handler suspects some vials may have frozen. For which of the following vaccines is the shake test an appropriate method to detect freeze damage?

• A Oral poliovirus vaccine
• B Measles-Rubella vaccine
• C Bacillus Calmette-Guerin vaccine
• D DPT vaccine ✓

Explanation

The shake test applies to adsorbed, freeze-sensitive vaccines such as DPT, TT, Td, Hepatitis D and pentavalent, where freezing causes irreversible clumping of the adjuvant that does not disperse within 10 to 15 minutes of shaking. The vial is compared against a deliberately frozen reference vial of the same product. OPV tolerates freezing, while BCG and MR are heat-labile but not tested by this method.

Reference: WHO Immunization in Practice: A Practical Guide for Health Staff, 2015 update ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.