During a training session on cold chain handling, a health worker asks about storing diluent for measles and BCG vaccines. Which practice is correct?

• A Store diluent in the deep freezer alongside the lyophilized vaccine
• B Never freeze diluent; keep it in the ILR at 2 to 8 degrees C the night before use ✓
• C Diluent can be stored at any ambient temperature and used directly from the shelf
• D Boil the diluent before reconstitution to ensure sterility

Explanation

Diluent must never be frozen, as freezing can crack ampoules and vials. The recommended practice is to refrigerate it in the ILR the night before a session so that reconstitution occurs at 2 to 8 degrees C, protecting the live vaccines from heat shock. Room temperature diluent can damage heat-sensitive reconstituted vaccine, and boiling is unnecessary because the diluent is supplied sterile and matched to each vaccine's volume.

Reference: WHO Immunization in Practice, 2015 update ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.