Conditioned icepacks or chilled water packs?

At PATH we are investigating a freeze prevention design that could be used to modify existing carriers or be incorporated into future carrier design. We are prototyping and obtaining temperature data on existing WHO PQS approved carriers with the addition of a thin Phase Change Material(PCM) liner box that surrounds the vaccines and prevents freezing by unconditioned or improperly conditioned ice packs. The cost of the PCM combined with the plastic liner box would be less than $15 assuming economies of scale. Preliminary data using environmental chambers suggests that this approach is feasible and that the PCM liner can allow for use of unconditioned ice packs without risk of freezing in most ambient conditions. We are in the concept development phase. Successful data/outcomes at this stage will then be tested in the field.

Dear Terry, Did you see our entry we put on Tech Net 21 regarding freeze protection using a wet towel as a barrier? Let me know if you need any future clarification. http://www.technet21.org/index.php/issue-90/a-simple-method-of-vaccine-freeze-protection.html

Dear Terry, I agree that changing habits is not easy... Can you be more specific with details of PCMs? For example what temperatute PCMs you are speaking about? And why do you think it is easier? Cheers UMIT

Hi Umit, Many thanks for the clarification on the WHO/PQS position on this. Whilst I fully subscribe to the cold water pack strategy, getting health workers in the field to even accept the idea of conditioned icepacks is difficult after they have been brainwashed with icepacks for the last 30+ years. Over recent months I have been sounding out health worker receptivity across a number of countries in West/Central Africa to cold water packs as an alternative to conditioned icepacks. The response is typically utter disbelief. Just a few weeks ago I made a presentation to a regional audience, and a senior WHO regional logistics executive present at the meeting strongly objected to the content of my presentation which promoted the use of conditioned ice packs or water packs. Changing habit is difficult. Changing technology is easier. A shift to phase change packs or something along the lines of an insulated sleeve/nylon basket inside currently used vaccine carriers would seem like an easier way to go than re-educating health workers around the globe. Best regards Terry

WHO still recommends that single antigen freeze-dried (lyophilized) vaccines and OPV should be distributed in cold boxes or vaccine carriers, lined with frozen icepacks. Field studies continue to show that vaccine freezing during transport remains one of the principal causes of damage to freeze-sensitive liquid vaccines in the cold chain. The use of ‘conditioned’ icepacks has previously been recommended as the way to avoid this risk; however icepack conditioning is a time-consuming process and recent cold chain surveys have shown that the practice is difficult to enforce and is widely ignored. You should note that the use of cardboard, newspaper or similar material to isolate freeze-sensitive vaccines from fully frozen icepacks is completely ineffective as a means for preventing vaccine freezing.. The only way to eliminate the freezing risk entirely is to transport liquid vaccines, other than OPV, in cold boxes lined with cool water packs which have been pre-cooled in a refrigerator to a temperature of +2°C to +8°C. Where it is essential to transport OPV, liquid and freeze-dried vaccines in a single carrier, experiments have shown that cold water packs may safely be used provided the cool water pack cold life of the carrier is not exceeded. These recommendations are based on the field studies organized/conducted by WHO that was published in PDA Journal of Pharmaceutical Science and Technology, Vol. 63, No. 1, January–February 2009 (Umit Kartoglu, Serge Ganivet, Stephane Guichard, Venkat Aiyer, Peter Bollen, Denis Maire and Birhan Altay). I am attaching this article as a further reference (This study was awarded by International Quality and Productivity Centre IQPC Best Logistics Project European Awards 2010 in Amsterdam, the Netherlands). Again, based on this article, "cool chain" was defined by the PQS (Performance, Quality and Safety) project and incorporated into E04 and E05 product sections. Cool life is defined as follows: "The empty container is stabilized at +43°C and loaded with coolpacks which have been stabilized at + 5°C for a minimum of 24 hours. Cool life is measured from the moment when the container is closed, until the temperature of the warmest point inside the vaccine storage compartment first reaches +20°C, at a constant ambient temperature of +43°C." The following documents could be viewed for more detailed information: http://www.who.int/immunization_standards/vaccine_quality/pqs_e004_cb01_2_pps.pdf http://www.who.int/immunization_standards/vaccine_quality/pqs_e004_vc01_2_pps.pdf PQS Guidance notes that will be available in a short time along with the launch of new PQS Database recommends the use of either 3 packs for vaccine transport: 1. Frozen icepacks (for vaccines OPV and single antigen freeze-dried (lyophilized) products) 2. Cool water packs (for all freeze-sensitive vaccines and wherever combination of OPV, single antigen freeze-dried (lyophilized) and freeze-sensitive products need to be carried together in one box) 3. Warm water packs (at extreme cold ambient temperatures for all vaccines) Along with this, WHO PQS no longer recommends the use of conditioned icepacks. Changing over to the use of cold water packs involves significant alterations in practice. In addition there are equipment implications because additional refrigerators will be needed at primary and intermediate level to cool the cold water packs in bulk. Consequently it is strongly recommended that the introduction of this method should be preceded by a formal cold chain study as described in WHO/IVB/05.01: WHO Study Protocol for Temperature Monitoring in the Vaccine Cold Chain. designed to establish the extent of current problems and the logistical and financial implications of the changeover.

Soren Spanner is the expert here. See CCL-Workshop-Report-Nov-2009.pdf and Soren and Mogen's views on Cool Chain. Soren Spanner and Mogens Munck paper and the Committee report are relevant to Cool Packs. The-cool-chain-concept-by-Soeren-Spanner-and-Mogens-Munck.pdf

I regret this doesn't answer your question but I hope it will be useful anyway: a paper published in Vaccines in 2006. Monitoring temperatures in the vaccine cold chain in Bolivia by Carib Nelson, et. al. It can be seen at: http://www.avasadevelopment.com/Tools_and_resources/pdf_file/TempColdChainBolivia.pdf. This showed that ALL vaccine shipments monitored in Bolivia were exposed to freezing temperatures. There is also a list of other references at the end of this article that may also be useful.

I'll forward your message to WHO.

Not sure about latest recommendations but you might look into the "Coldpack AntiFreeze Backpack Vaccine Carrier", which when I last spoke to Adrien Lehideux at Coldpack, met WHO/UNICEF Standard E4/VC2. Specification sheet (likely out of date) that I have from March 2009: BackPack Specifications-1.pdf Seen how much of the last mile distribution is often done by motorcycle or even bicycle, it always seemed to me that this product was an amazing and most insightful innovation. Likely that you can find out more on http://www.coldpack.com