POST 00226 : VACCINE FREEZING

Post0226 VACCINE FREEZING 8 February 2000 CONTENTS 1. CHANGING VACCINE STORAGE LOWER TEMPERATURE LIMIT FROM 0 TO 2 DEGREES? 2. MULTI FLOW REFRIGERATORS AND VACCINE FREEZING: CONTINUED 3. DOMESTIC REFRIGERATOR MODIFICATIONS? 4. REQUEST FOR ACTION ON FREEZING AND P.I.S. Moderators note: The moderator will be travelling from 11 February to 1 March 2000. While Internet connections and time are uncertain we hope to keep the TECHNET Forum online. Contributions to the discussions are welcome! ____________________________________*______________________________________ 1. CHANGING VACCINE STORAGE LOWER TEMPERATURE LIMIT FROM 0 TO 2 DEGREES? In TECHNET Post0218, T-ZONES & LOW TEMPERATURE PROTECTION, on 18 January 2000, [item 2. REFRIGERATOR TEMPERATURE RANGE 2'C TO 8'C?] Mary Catlin, PATH, proposed: * Considering the risk of freeze damaging HepB vaccine in zero degree storage - a vaccine coming into wide routine use, that we try to modify the recommendation to +2'C to Plus 8'C. * Mary also proposed that we do this in the TECHNET Forum. Robert Steinglass (BASICS), Soren Spanner (WHO/SEARO), Terry Hart (IT Power/India) and Michel Zaffran (WHO/V&B) discuss the this important issue. *The current WHO/V&B recommendation for EPI vaccine storage in refrigerators is for one month at 0 'C to +8'C. Other regions of the world and other countries recommend +2'C, or even +4'C to 8'C. * Hepatitis-B is only one of the many new freeze sensitive vaccines being introduced into national immunization programs around the world. The cold chain temperature limits were specified at a time when DPT with its much lower melting point( -3'C to -4'C). Action, comments and additions please: [[email protected]][email protected][/email] or use your reply button ___________________________________________________________________________ Date: Tue, 18 Jan 2000 08:01:03 -0500 From: "Robert Steinglass" To: "Technet Moderator" Subject: changing lower temperature limit from 0 to 2 degrees As the famous baseball player Yogi Berra said, "I am having 'deja vu' all over again." Many of us in WHO in the mid-1980's advocated for a 2 to 8 degree range (a change from the narrower 4 to 8 degrees range in existence since the start of EPI). But we were not at all happy to learn that the range would be changed to 0 to 8 degrees. To many people, we suspected that "0 degrees" (known as the freezing point) could be interpreted to mean "it's okay to freeze." Especially now with the introduction of hep B vaccine, some extra buffer to guard against freezing would be very important. While we are all talking about low temperature protection cut-offs and other modifications to the hardware, I think that practical implications a change in policy ("the software") should again be considered - just as Mary Catlin has proposed. Robert Steinglass --- From: "Soren Spanner" To: "Technet Moderator" Subject: Re: Post0218 T-ZONES & LOW TEMPERATURE PROTECTION Date: Tue, 18 Jan 2000 20:22:03 +0100 Since the early 70's there have been household refrigerators with automatic defrosting, either with a heating element attached to the evaporator or a thermostat that would allow the temperature of the evaporator be high enough to ensure that the frost melted before switching on again. These refrigerators did not freeze. I very much subscribe to the +2 to +8'C temperature range. soren --- Date: Thu, 20 Jan 2000 13:21:12 +0530 From: Terence J Hart To: Technet Moderator Subject: Re: Post0218 T-ZONES & LOW TEMPERATURE PROTECTION Hi Moderator, In reference to concerns about 0 or 2 degrees at the lower WHO temperature threshold. I would mention that we have checked a sample (several dozens of Vestfrost ILR's) against digital themometer probes inserted in the refrigerator compartment (sensor located close to the dial thermometer sensor provided with Vestfrost ILR's and find discrepancies of up to 4 Deg. I discussed this with Vestfrost at Technet and I understand the plan is to introduce a digital display. A sample was provided to me. I very much appreciate this measure taken by Vestfrost. If provision were made in the supply specification for refrigerator products to ensure resolution/accuracy of visual temperature indicators be within =/- 1 Degree, then WHO could safely accept 2-8 deg. or 2-10 as recommended storage temperatures. Best regards Terry Hart --- From: [[email protected]][email protected][/email] Date: Fri, 28 Jan 2000 18:23:09 +0100 To: , Subject: 2-8 degrees In reply to Mary Catlin's email of 14 January suggesting we set a standard of refrigerator temperature to be 2-8 rather than 0-8, I would like to offer the following comments, although, having now left the cold chain for a year things may have changed. First I should say that I also had the same idea a few years back, also because of the differences with the vaccines industry standards and vaccines package inserts and lab equipment. However, although, the 0-8 standard was set a little arbitrarily, by our friend John but this met the following needs 1. If you restrict the allowed temperature range to 2-8, you make it more difficult for the appliance to maintain that range hence more expensive machines 2. for some of the appliance working on gas, kerosene and solar, which we use a lot , if you restrict to 2-8, then the evaporator often will not get cold enough to freeze icepacks in the freezer compartment, or you would need two compressors or cooling systems and a more expensive appliance 3. finally, hep B does indeed freeze at-0.5 to -1 degree but a/.this is the temperature inside the vial and this corresponds to approximately -3.1 degrees in the fridge and b/ this is the scientific freezing point but there is, in fact, a substantial amount of supercooling down to -7.8 degrees before the vaccine actually crystallises and gets damaged by freezing. Studies were down at CRL, UK in the old cold chain days and published in the Technet newsletter of December 1990 which showed that only 2% of ten vials of Hep b failed to supercool while on the contrary we had more of a problem with DTP. (And thank you Libby for the very useful index you once did which enabled me to track down this information.) cheers, Michel PS: We do not have the electronic file of the Cold Chain News of that period so am unable to post the text today. ___________________________________________________________________________ Moderators note: Things change! More manufacturers and more products. ____________________________________*______________________________________ 2. MULTI FLOW REFRIGERATORS AND VACCINE FREEZING: CONTINUED in Post0212, VACCINES & COLD CHAIN, 26 November 1999, Anthony Battersby, FBA Analysts, posted an alert on Multi flow refrigerator - citing vaccine freezing temperatures in this type of domestic equipment, now being used for vaccine storage. Nan Miller, CDC-THS, responded to Anthony Battersby's Alert on Multi flow refrigerator in Post0212, VACCINES & COLD CHAIN, 26 November 1999, pointing out that this problem had been reduced in the Northern Territory Health Service in frost free domestic refrigerators with only minor modifications (i.e. thermal lag, appropriate storage patterns [loading], daily temperature monitoring) and good management. Anthony contacted Nan and reports that frost free equipment is not the same as multi-flow equipment and that multi flow equipment is a danger to vaccines. {See item 3. below for additional discussion] Action, comments and additions please: [[email protected]][email protected][/email] or use your reply button ___________________________________________________________________________ Date: Wed, 19 Jan 2000 06:23:42 -0500 From: Anthony Battersby Subject: Multi flow Sender: Anthony Battersby To: Dear Allan, I have had a reply from Nan Miller, it seems that the "frost-free" she is using is not A "multi-flow" refrigerator. I think we need to make clear that although multi-flow is also called "frost-free" there are other types about also called "frost-free" that are not multiflow. Multiflow is the type that I have been testing, I have now tested three other makes in another country with similar results. Multi flow can be recognised by the fact that they have two sets of controls, a thermostat and a thermo control, and always have a separate freezing compartment above the refrigerator cabinet. Anthony _________________________________*_________________________________________ 3. DOMESTIC REFRIGERATOR MODIFICATIONS? In the early to mid-1990s a lot of the cold chain equipment development and testing effort was put into the modification of domestic refrigerators to improve both performance and vaccine storage safety so that they would be made to meet the WHO vaccine storage temperature and hold-over standards. Using domestic refrigerators would allow a lower cost investment in cold chain equipment, equipment replacement, and possibly maintenance and repair. Terry Hart, IT Power India, points out that there are domestic refrigerator modification guidelines prepared by WHO consultants. Terry also expresses an interest in the modifications of multi flow equipment mentioned by Nan Miller in TECHNET Post0214, 07 January 2000, Nan Miller, CDC-THS, responded to Anthony Battersby's Alert on Multiflow refrigerator in Post0212, VACCINES & COLD CHAIN, 26 November 1999. Nan pointed out the very important role of modified domestic equipment and good management in minimizing vaccine freezing. Action, comments and additions please: [[email protected]][email protected][/email] or use your reply button ___________________________________________________________________________ Date: Thu, 20 Jan 2000 12:54:17 +0530 From: Terence J Hart To: Technet Moderator Subject: Re: Post0214 VACCINE FREEZING Dear Moderator, IT Power India did some validation of the draft domestic refrigerator modification guidelines prepared by WHO consultants. We used this guideline in one training programme, modifying 8 fridges with 8x2 particpants. Following this we updated the manual and then repeated the exercise at the next training session. We now have a usable manual and we have some data from temperature monitors which shows major improvements in performance. I would be very interested in obtaining a copy of modification procedures/guidelines used by Nan Miller in Australia. We would be interested in checking out this freezing problem with frost free systems on units we have access to. Happy 2k. Terry Hart ____________________________________*______________________________________ 4. REQUEST FOR ACTION ON FREEZING AND P.I.S. Soren Spanner, WHO/SEARO, kindly copied the Technet Forum his email to Hans Everts, WHO/V&B, suggesting action on low temperature protection and the WHo/UNICEF Product Information Sheets. Action, comments and additions please: [[email protected]][email protected][/email] or use your reply button ___________________________________________________________________________ From: "Soren Spanner" To: "Technet Moderator" Subject: Re: Post0218 T-ZONES & LOW TEMPERATURE PROTECTION Date: Tue, 18 Jan 2000 21:09:10 +0100 Hans, I suggest that we have a small meeting covering the domestic refrigerator and the 0' (or+2') cutout issues. May I also suggest that the new PIS be available on a CD soren ____________________________________*________________________