POST 00575E : VACCINE FREEZING

POST 00575E : VACCINE FREEZING Follow-up on POSTS 00571E and 00574E 28 June 2003 ______________________________________________ This posting contains three contributions. The first is from Pham Ngoc Len (mailto:[log in to unmask]) from UNICEF. He brings up an issue related to vaccine freezing, the shake test. The second contribution is from Alasdair Wylie (mailto:[log in to unmask]) bringing up many still unanswered questions. Finally Anil Varshney (mailto:[log in to unmask]) from India further contributes to the discussion. Besides many practical suggestions, please note that he also raises questions about the shake test. This could deserve a separate discussion. ______________________________________________ 1-- Yes, it is good to dialogue on this issue. I have the experience that whatever we try to improve, if the suppliers of the vaccine did not take this seriously then it become less useful. When vaccine was frozen then the shake test was used to identify the damaged vials of the shipment. The question is the validity of the shake test, and how to get a correct sample for this exercise remains a question. Pham Ngoc Len ________________________________________ 2-- A few comments, and some more questions and suggestions on this issue, though not restricted to the "cold climates" scenario: 1. Yes it is not just refrigerator performance and control. Vaccine freezing in transport between district/health centre/outreach sessions has been found in the past (eg Pakistan EPI review 1998) and one suspects is still a continuing and frequently unobserved/unreported/undocumented problem in many places. In 2001 a vaccine freezing investigation was to be initiated in Nepal by SEARO following reports of DPT freezing during an EPI assessment there which I led in 2000. It would be interesting to know what the study findings were and what if any changes in vaccine management were made as a result. I note that this study was not mentioned in the "Technology and Operations Panel" (TOP) February meeting report on Overcoming Freezing in the Cold Chain (Post 00566) 2. Vaccine freezing risks, risk assessment and prevention should be a standard element in all logistician's basic and refresher training and should also be on the agenda at all regional managers meetings.. Was it included in the recent AFRO logisticians workshops? And is it included in any planned such regional/subregional workshops or training elsewhere? (none shown on training courses section of TechNet website.) Is it on the agenda at the next EMRO Regional Managers meeting starting 29 June? While policy and new hardware development for the future is underway, best efforts must be made now to help managers and staff understand risks and minimise them, using what tools and procedures they have available now, specific to country circumstances. The FreezeWatch indicator and the Shake Test have both been available for about 20 years and have been substantially neglected for reasons that are essentially management rather than technical. (Does this sound familiar?). New or updated one page "Job Aids" (PATH has good examples) should be prepared and widely disseminated, but are not of course sufficient in themselves as Mr. Baru quite rightly points out. 3. Is the "Technology and Operations Panel" (see above) - nothing about which was mentioned on TechNet Forum until the report of the February meeting came out - in effect to act as the working group on prevention of vaccine freezing which is one of a number of TechNet working groups which were to have been formed after the 2001 New Delhi TechNet meeting, or if not what is happening?. There are other questions/issues raised but apparently still awaiting answers for example on Hep B freezing temperature and its implications, last asked Post 00506 last October. 4. FreezeWatch reliability: Purchasing was suspended on WHO advice in May 2002 (Post 00470) following field reports of apparently incorrect/unreliable activation. This issue was asked about at the February TOP meeting referred to above and the meeting report received in May includes a footnote advising that WHO lifted the purchase ban on 6 March 2003. Nothing has been reported on TechNet about this or about the findings of the investigation which was undertaken because of the field reports. Even if other mechanisms are being used to communicate information on purchasing matters to regional and country offices it would presumably be useful to let TechNet members know? Best regards Alasdair Wylie __________________________________________ 3-- I wish to compliment PATH and WHO for compiling the data on freezing of vaccines. This has provided the insight that vaccine freezing is an issue which needs to be addressed. I feel instead of quantification, one must try and undertake remedial actions at different levels, from service delivery to national. The subject of freezing is as old as the immunization programme and freezing takes place not by design but by lack of knowledge/information, training, understanding of the cold chain, supervision and monitoring. It happens in all stages and at all levels from country level to the service delivery levels. What is needed is the percolation of the knowledge and information on how to stop freezing turned into SIMPLE ACTION POINTS with clarity for each level in their respective fields. Some observations based on visits as well as studies on cold chain logistics show that freezing is quite common in cold areas in mountains and becomes unavoidable due to lack of electricity and ambient temperatures being very low . Even disconnecting the fridge will not help as ultimately it will reach ambient temperatures. The following have also been noted concerning freezing. The Hepatitis B froze within 2 hours of taking out from cold chain store into the vaccine carrier due to direct contact of the vial, shake test was negative, the health personnel was not aware of the consequences of the freezing and the vial was thawed and used. Similarly vaccines kept in cold boxes during cleaning and defrosting of the refrigerator, Hep B, DPT , TT froze due to direct contact. However Hep B vials in individual packing did not freeze. This was also verified by demonstrating the same during a training session on Immunization. Thus proving the usefulness of cartons preferably made of thermocool or plastic or even cardboard to protect from freezing. Even after 48 hours of direct contact with icepacks, Thermocool was the best. In warmer climate freezing happens when there is disruption in electric supply. On restarting of electricity, cooling is more leading to freezing of vaccine vials lying at the lower level Another observation was that when the vaccines were frozen for 2 to 6 hours the shake test was negative, no flocculation sediment occurred, however those frozen for 10 hours or more (overnight) showed positive shake test – any explanation ? What effect on potency and sero conversion, Serum Institutes studies also do not provide answer to this observation. Some Options as Action Points suggested : 1. The vaccine vials should preferably come in plastic packing individually or cardboard (plastic is better). This will lead only to 2- 5% increase in total volume for storage. And at most peripheral service delivery points, NO additional space will be required 2. Use Freeze Watch universally at all levels (with instructions in BOLD that "DO NOT USE" if the freeze watch shows leakage of fluid) as the vaccines are now destroyed and not valid. 3. While storing at district / PHC level use Thermocool boxes to keep the freeze sensitive vaccines. (This will delay freezing). 4. The ILR should carry markings on the side where to keep which vaccines 5. Important instructions like “FREEZING DESTROYS VACCINESâ€