Pharmacy & cold chain

Holding the vaccine cold chain

Purpose-built refrigeration, continuous monitoring and the excursions that quietly waste stock.

Departments: Pharmacy & Clinical Logistics · Medical & Healthcare

Vaccines are generally stored between +2 °C and +8 °C unless the manufacturer specifies otherwise, and some products have their own frozen or ultra-cold requirements. Always follow the manufacturer's storage instruction and your national immunisation programme's current guidance for the specific product. Everything below is about the equipment and routine that keep you inside that window.

A domestic fridge is not a vaccine fridge

This is the most common and most expensive error. Domestic refrigerators cycle widely around their setpoint, run coldest at the back and warmest in the door, and have no alarm when they drift. A purpose-built pharmaceutical or vaccine refrigerator holds a tight, uniform temperature, recovers quickly after the door opens, and alarms on excursion. If your stock is worth more than the price difference — and it almost always is — the decision makes itself.

Specifying the unit

• Capacity. Size for peak campaign stock, not routine stock, and never load above the manufacturer's fill line — airflow is what holds the temperature.
• Alarms. High and low temperature alarms, an audible alert, and a power-fail alarm. Confirm the alarm still works when the power is out.
• Recording. Built-in min/max recording at minimum; a downloadable log is better.
• Door. Glass doors let staff look without opening, but confirm the model is rated for your ambient conditions. A lockable door is worth specifying.
• Power resilience. In load-shedding conditions, ask about hold-over time and whether the unit tolerates repeated interruption and restart.

Monitoring that actually catches a problem

A daily min/max reading written on a chart is the minimum, and it only tells you that something happened, not when. Continuous electronic monitoring with a logger — ideally one that sends an alert to a phone — is what catches an overnight failure before the stock is lost. Whatever system you use, place the sensor with the vaccines in the body of the fridge, not on a shelf bracket or against the wall.

Daily routine

• Record minimum, maximum and current temperature at the start and end of each day, and reset the min/max after recording.
• Rotate stock by expiry, shortest first, and keep vaccines in original packaging.
• Never store vaccines in the door, and never store food or specimens in the vaccine fridge.
• Leave space between boxes for air to move.
• Keep conditioned water bottles in unused space to buffer the temperature. Do not put ice packs inside a +2 to +8 °C refrigerator — they create a freezing risk against the vaccines.

Excursions

Write the procedure before you need it: quarantine the stock, label it clearly as not for use, record the duration and the temperature reached, and contact the manufacturer or your programme for a viability decision. Do not discard and do not use until that decision is made. The most damaging response to an excursion is an improvised one.

Transport

The chain does not stop at your door. Specify validated cold boxes and conditioned ice packs for outreach, and put a logger in the box. Ice packs straight from a freezer can freeze vaccines against the wall of the box — conditioning them until they begin to sweat prevents that.