POST 00416E : FREEZE PROTECTION IN VACCINE REFRIGERATORS

POST 00416E : FREEZE PROTECTION IN VACCINE REFRIGERATORS 21 January 2002 _______________________________________________________________________ Carib Nelson Technical Officer at Program for Appropriate Technology in Health (PATH) is requesting your opinions on freeze protection in refrigerators. Please send your input to both Carib and Technet. _______________________________________________________________________ In considering ways to reduce inadvertent cold chain freezing, some refrigerator manufacturers are considering putting heating elements in their vaccine refrigerators that would automatically turn on when the internal temperature approaches freezing. This approach could keep vaccines safe in situations where ambient temperatures within health centers fall below zero. If this could be combined with better controls where the refrigerator will not cool when its temp is below 1°C--regardless of what the operator sets it at--we might have a freeze-proof refrigerator. Obviously this is not a fix for protecting vaccines from freezing during cold-box-with-ice-pack transport. We are seeking input on the heating element approach, specifically: 1. Are freezing temperatures within health centers, or wherever refrigerators may reside, a common occurrence? (or is it improper thermostat adjustment that causes most refrigerator freezing)? 2. What minimum temperatures should we try and protect against with this approach -- keep in mind that these would be minimum temperatures in health centers, or where ever the refrigerator sits, not minimum ambient temperatures. 3. Could we come up with a specification for freeze protection ("refrigerator must maintain internal temperatures of not less that 1°C when refrigerator is placed in -10°C environment for 48 hours....")? We are not going to save the vaccine during a 2-week power outage in Siberia in December, but if we could describe the more common scenarios of low temperature exposure, manufacturers may be able to take steps to provide some protection. Thanks for your input. Carib Nelson Technical Officer Program for Appropriate Technology in Health (PATH) 4 Nickerson Street, Seattle, WA 98109-1699 USA Telephone: (206) 285-3500; Fax (206) 285-6619 _____________________________________________ ----------------------------------------------------------------------------- All members of the TechNet21 e-Forum are invited to send comments on any posting or to use the forum to raise a new discussion or request technical information in relation to immunization services. Starting in January 2002, TechNet21 e-Forum will have 3 language versions: English, French and Spanish. The comments made in this forum are the sole responsibility of the writers and do not in any way mean that they are endorsed by any of the organizations and agencies to which the authors may belong. ----------------------------------------------------------------------------- CONTRIBUTIONS: Contributions to: or use your reply button! The TechNet21 e-Forum welcomes new subscribers who are involved in immunization services. SUBCRIBE: To subscribe, send an e-mail to: Leave the SUBJECT area BLANK, do not type anything. In the body text, just write: Subscribe TECHNET21E Surname Name Do not use any accents in your name and surname. UNSUBSCRIBE: To unsubscribe, send an e-mail to: Leave the SUBJECT area BLANK, do not type anything. In the body text, just write: Unsubscribe TECHNET21E ------------------------------------------------------------------------------ ARCHIVES New archives of posted messages starting with 1 November 2001 is accessible to all TechNet21 subscribers. To view the archives: http://listes.ulaval.ca/listserv/archives/technet21e.html Archives for postings between 17 August 1998 and 31 October 2001 can be found at the following web site for download starting 1 December 2001. http://www.who.int/vaccines-access/Vaccines/Vaccine_Cold_Chain/Technet Archives for files (documents) are under revision to clean old documents and drafts that are already replaced with new ones, and will be made available soon at the same site. http://www.who.int/vaccines-access/Vaccines/Vaccine_Cold_Chain/Technet ----------------------------------------------------------------------------- The World Health Organization and UNICEF support TechNet21. The TechNet21 e-Forum is a communication/information tool for generation of ideas on how to improve immunization services. It is moderated by Claude Letarte and is hosted in cooperation with the Centre de coopération internationale en santé et développement, Québec, Canada (http://www.ccisd.org) -----------------------------------------------------------------------------