TechNet-21 - Forum

This forum provides a place for members to ask questions, share experiences, coordinate activities, and discuss recent developments in immunization.
  1. Isaac Gobina
  2. Cold chain equipment
  3. Thursday, 01 November 2018


The WHO PQS product feedback cycle

Did you know that at the heart of WHO Performance, Quality & Safety (PQS) is a crucial performance monitoring and feedback mechanism? This mechanism makes it possible for PQS to enforce and improve product standards and make sure that products and devices procured for use in immunization programmes are suitable, quality and reliable. This cycle of feedback and improvement is powered by the input of EPI programmes and product manufacturers. In-field insights - such as reports of product life cycle performance or defects and faults - help WHO PQS develop new or review existing product specifications to maintain a robust prequalification process and, ultimately, help EPI programmes safeguard and deliver precious potent and safe vaccines.

Envisioning the future

WHO PQS also gathers up-to-date insights about the evolving requirements of product users’ operating environments, with which PQS can help shape the design of novel product features. Desired future product features are incorporated into PQS target product profiles (TPPs) as aspirational targets for manufacturers’ product development. Recent examples of technical advancements thanks to PQS TPPs include remote temperature monitoring devices, and solar power energy harvesting capabilities. Both of these advances answer current needs of product technicians and other health centre staff, reinforcing abilities to deliver reliable vaccination services.

Five minutes to fruitful feedback!

So, calling all product users and product manufacturers to help improve performance and drive innovation of immunization products and devices!

Tell us about any product defects as they happen, and take a moment to imagine your dream-features for any PQS products:


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Larry Schlussler Accepted Answer

I have a suggestion for hot zone testing. It is benefical to have PQS test conditions not be unnecessarly restrictive and reflect real climatic data. I don't think a location can be found where day time reach 43 Deg C and night time temperatures remain near this high. In north Africa for example, day time temperatures may reach 43 Deg C but night time temperatures are much cooler.

What I suggest is that for a hot zone there will be no stable run test at 43 Deg C and that the test be replaced by a day/night test with appropriate temperatures. The appropriate temperatures would be determined from climatic data for locations deemed most critical.

Making a test conditions at one end of the temperature scale unnecessarly restrictive can effect reliability at the other end of temperature scale. For example if an SDD refrigerator is using ice for phase change storage the refrigerator compartment must be in relatively close thermal contact to the stored ice so that storage temperatures remain below 8 Deg C at an ambient temperature of 43 Deg C, this close thermal contact will make it difficult to maintain temperatures above 2 Deg C in a 10 Deg C enviorment. Having  test temperatures remain at 43 Deg C for 24 hrs will amplify this problem.

One further suggestion is that the MKT temperatures be used for all stable run tests to evaluate the effect of temperatures straying above  8 Deg C. Currently transient temperature above 8 Deg C are allowed, using MKT temperatures would quantify the effect of these temperatures excursions. Using MKT temperature would also allow manufactures and designers to know exactly how much of a tempeature  excursion is acceptable.

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  1. more than a month ago
  2. Cold chain equipment
  3. # 1

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