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[Unpublished] 1986 Jan 8.  p. (HPM/EPI C12/20/1)The Pan American Health Organization/World Health Organization (PAHO/WHO) has changed its initial recommendation concerning the temperatures for storing unfrozen vaccines to 0 degrees Centigrade to 8 degrees Centigrade from the previous recommendation of not below 4 degrees Centigrade (with an upper limit of 8 degrees Centigrade). Most, but not yet all, current Expanded Program on Immunization (EPI) documents carry this new recommendation, and it will be revised in old documents as they are updated. This decision has been the source of several heated debates among the technical staff. 2 factors swayed the decision to make this change: In some links of the cold chain, which depend on ice, there is no alternative but to allow a lower limit of 0 degrees Centigrade; and the result of studies of temperatures required to freeze DPT before freezing occurs. The change makes the current recommendation consistent with current practice and does not appear to pose a threat to the potency of the DPT, DT, or T vaccines. Some diluent may freeze at 0 degrees Centigrade, but this only causes a problem if freezing breaks the diluent vial. This has not been observed at 0 degrees Centigrade, although it has occurred at lower temperatures. 1 of the reasons for the debates over making this change is that it violates the principle of giving clear and consistent advice to the health workers carrying out the operations. Yet, in this case the feeling is that due to the various considerations explained, the new recommendation is justified.
[Unpublished] 1985. 8 p. (EPI/CCIS/85.2)This protocol provides a method for using Vaccine Cold Chain Monitors to make periodic reviews of a national cold chain. This protocol is based on experience that has been gained from information from 31 countries and from cold chain reviews in India and Tunisia. The purpose of a cold chain review is to make a nationwide or regionwide review of the effectiveness of the vaccine cold chain; and to find out how best to redirect cold chain development efforts into the areas that most need help. A review method is outlined and should be modified according to local conditions. A cold chain review should take about 7 months to complete and should be timed to precede or coincide with a wider EPI and primary health care review. A timetable is included. For the review: monitor cards are distributed with vaccine shipments from the manufacturers so that cards reach all cold chain stores; at each store in the cold chain and at each transport link, the cold chain monitor arriving with vaccines is checked, and any failures registered by the indicators are recorded on the monitor card; monitor cards are returned to a central office for sorting and analysis; and the results of this analysis then are used as a guide to identify and strengthen the weakest links in the cold chain. How many cold chain monitors are needed for a review depends on the size of the study area and the extent to which the monitors will be used. In general, each dispensary and outreach immunization session should receive at least 1 monitor card that has traveled through the cold chain from the central store during the study period. An extensive training program is needed before the review can begin. All health workers who will handle vaccines during the study must receive some training on how to fill in and interpret the readings on the monitors. Once the materials have been written, this training should be conducted in 3 steps for regional and district supervisors and maternal and child health staff and health assistants who work in health posts and outreach centers. The analysis of the results can be organized in many different ways. Each monitor that has been returned from a health center can have up to 23 items of information on it.
[Unpublished] 1983. 10 p. (EPI/CCIS/83.7)At this time in many developing countries sterilization practices for syringes and needles which are used to provide immunizations remain unsatisfactory. Problems include the use of the same syringe to administer vaccines to different persons and inadequate sterilization methods. The project objective is to explore the economic and technical feasibility of 2 approaches to improve these problems: the development of inexpensive sterilizable plastic syringes and the development of steam sterilization methods which are effective and convenient. Laboratory tests now have been conducted on sterilizable plastic syringes from 3 manufacturers and on pressure sterilizers from 2 manufacturers. The syringes gave satisfactory performance after 200 sterilizations equivalent to about 1 year's full use. The sterilizer tests demonstrated that 20 minutes of steam pressure is adequate to achieve sterilization. Field trials are to be conducted in up to 5 countries during 1983 and 1984 and results are expected to be published by the end of 1984. 0.1 ml single dose, sterilizable plastic BCG syringes were developed by 2 manufacturers, and prototype glass 0.1 ml syringes were made by 1 manufacturer. These syringes were tested in the laboratory together with a standard 1.0 ml glass BCG syringe and 2 sterilizable plastic 1.0 ml syringes intended for use with DPT, tetanus, and measles vaccines. The results of these tests are summarized in Table 1, and the test protocol appears in Annex 1. The sole recurring problem identified by field workers was the difficulty in releasing air bubbles from the syringe. 2 manufacturers were selected out of 13 manufacturers of domestic pressure cookers who demonstrated high performance in European and North American consumer tests. Sterilizers of 2 sizes were developed by modifying domestic pressure cookers to oeprate at temperatures between +121-132 degrees centigrade. Racks were developed to suspend syringes, needles, and other immunization instruments to hold them securely during transport yet also to offer easy access during the immunization session. The sterilizers were tested for steam distribution, safety, fuel consumption, and sterilizing performance; the results are summarized in Table 2.