Oral poliovirus vaccine (OPV) is stored at what temperature in the primary cold chain, and what is the 'shake test' used to assess?

• A OPV is stored at 2°C to 8°C; shake test assesses heat damage to OPV
• B OPV is stored at –15°C to –25°C; shake test determines if OPV has reached room temperature
• C OPV is stored at –15°C to –25°C; shake test assesses freeze damage to adsorbed vaccines ✓
• D OPV is stored at 2°C to 8°C; shake test assesses freeze damage to DPT/hepatitis B vaccines

Explanation

OPV must be stored at –15°C to –25°C in the primary cold chain (district and sub-district levels) to preserve viability of the live attenuated virus. The shake test is used to detect freeze damage in vaccines that should NOT be frozen — specifically adsorbed vaccines such as DPT, DT, TT, hepatitis B, DPT-HepB, and pentavalent vaccines. Frozen adsorbed vaccines lose potency and show clumping that does not disperse on shaking, unlike fresh unaffected vaccine. OPV itself is tolerant of freezing and this test does not apply to it.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

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Written and medically reviewed by the StethoPrep medical team.