What PQS is — and isn't
WHO publishes performance specifications for each type of immunization device, then lists products that have been verified against them. WHO describes these as minimum requirements for products used to store, transport and administer vaccines. The catalogue is public and searchable.
PQS is not a general medical-device approval and it is not an Indian regulatory licence. It answers one question for a programme buyer: has this model been independently shown to meet WHO's specification for its category?
The equipment categories
Products are grouped by category code. Refrigerators and freezers sit in E003. Neighbouring categories include E001 for cold rooms and freezer rooms, E004 for cold boxes and vaccine carriers, E005 for coolant packs, E006 for temperature monitoring devices and E007 for cold chain accessories such as voltage stabilisers. A complete vaccine store often draws on several categories, so a 'PQS' requirement in a tender may apply to the logger and stabiliser as well as the fridge.
How to read an E003 refrigerator listing
| Field | What it tells you |
|---|---|
| Status and valid-until date | Whether the model is currently prequalified; suspended or withdrawn products should not be purchased |
| Climate zone | The ambient conditions it was tested for; listings marked 'Hot' commonly show testing at 43 °C |
| Minimum rated ambient | The coldest room it is rated to run in without freezing its contents |
| Freeze protection grade | How well the design guards stored vaccines against freezing |
| Hold-over time | How long it stays in range after power is lost |
| Energy source and lining | Mains, or solar direct drive; regular or ice-lined |
| Storage capacity and energy use | Net vaccine storage in litres and kWh per day under test conditions |
| Specification reference and verification lab | Which PQS specification it was tested against, and who tested it |
Why these fields matter in India
The climate-zone and hold-over fields map directly onto Indian problems. A unit tested at 43 °C ambient is being judged in conditions close to a non-air-conditioned summer store room. Hold-over is the protection you have during the power cuts many districts still see.
Freeze protection deserves equal weight. Freezing damage to freeze-sensitive vaccines is a well-documented cold chain risk, and a design rated for freeze protection reduces it without depending on staff habits. Solar direct drive units, which run from solar panels without a battery, are listed for sites with little or no grid power.
Who actually needs PQS equipment
- National and state immunization programmes, and projects funded through UN agencies or major donors, commonly require prequalified equipment for vaccine storage.
- Private hospitals, clinics and pharmacies are generally governed by product labels and their drug control authority rather than PQS — but a PQS listing is still useful evidence when comparing models.
- Laboratory, pharmaceutical and biobank storage outside vaccines is outside PQS's scope; other standards and in-house qualification apply.
How to check a 'PQS' claim
Ask for the PQS code of the exact model, then look it up in WHO's online catalogue. Check that the manufacturer's reference matches, the status reads prequalified, the valid-until date is in the future and the climate zone suits your site. A brand having one prequalified model says nothing about its other models, and a lookalike cabinet is not covered by its sibling's listing.
If your funder or programme specifies PQS equipment, treat the catalogue as the only proof. If it doesn't, you can still use PQS listings as a benchmark for what good hold-over and freeze protection look like.
Frequently asked questions
- Does PQS prequalification mean a fridge is approved in India?
- No. PQS is WHO's verification for immunization devices, used mainly by programmes and UN procurement. Indian licensing and storage rules come from CDSCO, State Drugs Control authorities and, for programme vaccines, the national immunization programme.
- Is a PQS listing permanent?
- No. Each listing carries a status and a valid-until date, and products can be suspended or withdrawn. Check the live catalogue on the day you buy.
