POST 00502E : CHILLED WATER PACKS STUDY

POST 00502E : CHILLED WATER PACKS STUDY Follow-up on Posts 00485E and 00501E 20 September 2002 _______________________________________________________________ Ümit Kartoglu (mailto:[log in to unmask]) brings further clarifications on the chilled waterpacks study. _______________________________________________________________ Samuel's contribution did not really fit into "chilled water packs study" as a subject since the study had no intention to go beyond the vaccine transportation from primary to intermediate vaccine stores and to service level as well. In his contribution he highlights his concerns on "the use of cool or wet icepacks during the measles administration after the reconstitution." In the original POST00485E, the very first sentence was as follows: "In Post 00400E (20 December 2001), I asked several questions that led WHO to conduct a series of studies both in laboratory-controlled and field conditions using chilled water packs during vaccine transportation." In this posting, no reference was made to using this technique for outreach sessions to keep reconstituted vials cold. In this regard, Samuel's contribution is wrongly questioning the approach. However, the question could be phrased as whether chilled water packs can be used for conducting outreach sessions with freeze-dried vaccines, which deserves a different level of discussion. The whole idea of the chilled water packs came as an option to prevent exposure of freeze-sensitive vaccines to freezing temperatures during vaccine transportation. I have to admit that as a matter of fact and unfortunately, the use of frozen icepacks without any conditioning (from freezer directly into the cold box) is still recommended/practiced by some national immunization services. In order to prevent any future confusion, I would like to underline once more the logic behind the study on the use of chilled water packs in vaccine transportation: 1. Current policy recommends that icepacks be conditioned to have sweat (beads) on the surface of the icepacks before loading the cold boxes. However, studies conducted show that with this conditioning method, vaccines are still in danger of freezing. Field observations also show that in many cases, frozen icepacks without any conditioning are used for transportation, thus putting vaccines at greater risk of freezing. 2. "Full conditioning" of icepacks as recommended in the "Guideline for establishing or improving primary and intermediate vaccine stores" (POST00400E dated 12 December 2001) was not found practical since it requires around one hour of conditioning at an ambient temperature of 20°C. Preliminary discussions with EPI managers during the 9th TFI meeting in Addis Ababa (December 2001) underlined that the recommended guideline to be followed is far from being realistic and practical. 3. Chilled water packs are the choice of coolant to accompany freeze-sensitive vaccines during international vaccine transport. The validation of packaging/shipping procedures conducted by vaccine manufacturers shows that chilled water packs can keep vaccines safe even at a continuous ambient temperature of -5°C for at least 48 hours (inside temperature not dropping below +2°C). 4. If packed together in the same cold box, there is no technology available today that provides necessary "cold" temperatures for OPV while preventing freeze-sensitive vaccines from freezing. 5. The current acceptable exposure period of vaccines to higher temperatures during transport as indicated by Cold Chain Monitor cards allows most of the freeze-sensitive vaccines up to 2 weeks at 12°C to 21°C. Country level vaccine distribution from primary to intermediate stores or intermediate stores to service levels does not take more than the days limit set as a rule in Cold Chain Monitoring. As seen above, the study aims at finding an alternative vaccine transportation approach to remove the freezing risk. Those interested in the study protocol, please contact Dr. Ümit Kartoglu directly at : (mailto:[log in to unmask]) ----------------------------------------------------------------------------- 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. 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