1. Ian Lester
  2. Vaccines and delivery technologies
  3. Thursday, 14 May 2020

Dear All,

I was recently asked to write an article about "getting ahead of the curve" in terms of capacitating the cold chain in anticipation of the Covid-19 vaccine and of course as the world starts to lift the lockdown, the imminent catch-up programs for routine vaccination programs . I would welcome your thoughts and comments.



Ian Lester


  1. https://www.businesslive.co.za/bd/opinion/2020-05-06-build-an-effective-global-cold-chain-in-anticipation-of-covid-19-vaccine/
Accepted Answer Pending Moderation

Thank you starting this discussion, Ian.
The short answer to the question of immunization cold chain readiness is probably no, not entirely.
In response to the question of cold chain (CC) preparation for a possible covid 19 vaccine we are at the disadvantage of not knowing what our CC challenge(s) will ultimately require. We do know that not all fridges are created equally and even well-developed countries do not always use fridges with correct temperature control leading to vaccine waste or worse. If we were to assume that a new vaccine will require a commonly used acceptable vaccine storage temperature range of +2C to +8C with no freezing allowed then we can imagine that the WHO PQS family of prequalified fridges would support the effort.
However, all of the present day PQS prequalified fridges are either electric mains (grid) powered ice lined refrigerators (ILR) used when electricity is not reliable or solar powered appliances, most now being battery-free solar direct drive (SDD), used where there is no mains supply or the mains is not reliable .
But what about those places where reliable electricity is found? These fortunate places are both in some developing countries as well as the most developed countries. With reliable power the ILR or SDD may not be the most cost-effective match. In anticipation of a global need for lower cost mains powered vaccine fridges WHO PQS established a category for such a fridge (see WHO PQS E003/RF01 documents on the PQS website). This category was intended for lower cost vaccine fridges that could easily leverage “domestic” fridge manufacturing techniques already widely known and already used in fridge factories around the globe. Based on “domestic” fridge testing supported by Project Optimize it appears only a few modifications are needed for a “domestic” fridge with reliable mains power to meet PQS requirements. These include slightly better temperature control and a 4-hour holdover after power cut. These modifications are also already well known and do not require high tech developments. PQS lab testing for low mass fridges will be shorter and less costly than lab testing for high mass ILR’s and SDD’s that have longer holdover (or autonomy) requirements (and usually ILR and SDD will have some unique manufactured features).
These fridges may even find application in the most developed countries when appropriate national standards are not used to specify cold chain equipment leading to decentralized decision making vulnerable to pressures to buy “domestic” type fridges that then may be substandard – even dangerous - for vaccine storage. In such cases the WHO PQS offers a path to improve mass produced, lower cost, low mass fridges for more assured vaccine temperature control and storage. Such an effort is both technically possible, easily adapted by manufacturers around the globe and attainable in a relatively short period. Sadly, to date, there are no PQS prequalified vaccine fridges (in the PQS E003/RF01) for what may be a very large market.
I suggest any country – large, small, developed or developing – consider upgrading from any fridge that does not meet today’s known vaccine temperature storage requirements. For locations with very reliable electric grids then it is time to develop some lower cost, low mass fridge solutions – now. A weak cold chain must be strengthened to both better conserve the known vaccines and be ready in the event we need the same temperature controls for covid vaccine.
Steve McCarney
Director – Sunny Day LLC

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