POST 00494E : PROTECTION OF MORE COLD-SENSITIVE VACCINES

POST 00494E : PROTECTION OF MORE COLD-SENSITIVE VACCINES Follow-up on Posts 00400E, 00412E, 00419E, 00428E, 00475E, 00480E, 00482E, 00484E, 00490E and 00491E 31 August 2002 ______________________________________________________________ Anthony Battersby (mailto:[log in to unmask]) from FBA Health Systems Analysts, UK makes two contributions about the two previous postings on the issue (00490E and 00491E). For practical purposes his contributions are regrouped into one. Robert Steinglass (mailto:[log in to unmask]) from BASICS, USA forwarded questions asked by Felicity Cutts and Allan Bass (my apologies to both for not having requested their approval to post these) and adds his own concerns, building on his previous contributions. Finally, Ãœmit Kartoglu (mailto:[log in to unmask]) sent a reference to WHO document on the thermostability of vaccines that addresses some of the expressed concern. Only a portion of it is reproduced here but for those who would rather consult the complete version, the link is also indicated at the bottom. ______________________________________________________________ 1- With respect, what we think about sub zero hep B is not really relevant, unless the manufactures will endorse the findings. What steps are being taken to bring the manufactures on board? Is it not the responsibility of the manufactures to identify if their vaccine can be used when it has been stored below zero? How do you use vaccine in a 'super-cooled state' stable state? My experience from trying to handle DPT that was super cooled was that it changed state as soon as it was shaken. 2- The following extract is from the WHO guidance : "To avoid this, reconstituted BCG, measles and yellow fever vaccines must be kept cooled, and must be discarded after 6 hours after reconstitution." I fear that it is too vague what is cool? if the ambient is 43°C then +37°C is cool and that is a temperature at which measles will rapidly loose potency as well as being likely to become contaminated (see page 26 stability of vaccines who/epi/gen/89.8) The guide should specifically state that reconstituted vaccine must be stored for no more than 6 hours at safe temperatures i.e. +2°C/+8°C. I think the technical message from WHO to Technet needs to be more explicit and briefer. e.g " VITAL FOR SAFETY OF THE CHILD:- reconstituted vaccine must always be stored out of direct sunlight at temperatures between +2°C and +8°C and must be discarded within 6 hours of reconstitution. THERE ARE NO CIRCUMSTANCES WHERE THIS ADVICE MAY BE IGNORED." Anthony ________________________________________________________________ From Felicity Cutts: I think there are some old literature on the effect of reconstituting measles vaccine with warm diluent. Artur Galazka would have known of course. My memory is that it destroys the vaccine but I don't know how fast. Presumably if it is actually at ambient temperature it could kill the virus quickly. Perhaps Clem could check with John Lloyd if he remembers the original experiments that were done - as well as the manufacturers. Julie Milstien may also have better memory than me. Hep B is not supposed to be frozen - again the manufacturers should be able to tell us what exactly happens if it is frozen. Presumably CDC should have a briefing pack on these issues for their field staff. Felicity ______________ Do you know if the vax vial and diluent are at cold chain conditions when reconstituted? If not it would be even worse. regards, Allan ______________________________________________________________ I think Felicity (see above) raises an important point. Are the implementing staff from WHO, UNICEF and CDC, who are planning campaigns in the field, issued with an essential briefing package of materials and operational guidance from WHO on vaccine safety issues like the V&B Update attached to Post 00491E? If not, could it be done as a matter of urgency....?! I am concerned that there is little attention given in the planning for measles campaigns (in such difficult countries as DR Congo, for example) on the need to keep reconstituted measles vaccine cold for safety and potency reasons. I was at a Red Cross meeting several months ago where, after expressing my concerns, I was lectured by a junior CDC staff that my concern was irrelevant as the vaccine is used so quickly. The need to keep measles cold after reconstitution is viewed by many agency staff as an inconvenient detail which need not constrain organization of the campaigns. Operations and technical officers have been replaced in nearly all countries by medical epidemiologists who do not share the same perspectives.... WHO is largely silent on such matters. Maybe UNICEF needs to fill the gap technically in the area of stock management and logistics. The update is a reminder that WHO policy is clear regarding the need for ice on measles campaigns and during routine services. How exactly is that to be done? Making, storing and distributing as much ice as is required for simultaneous immunization by many teams during a measles campaign is a huge logistic challenge (a much greater problem than for polio NIDs) and requires serious attention in the planning for campaigns. Just think about the challenges faced by DRCongo! Are our counterparts in the MOH and other agencies paying sufficient attention to the need for safety and quality???? Are their logistical experiences on these campaigns being documented?? I am surprised how little discussion there is on this topic. Are logisticians from international agencies being engaged on these campaigns? This is not an issue of vaccine potency only, it is also an issue of safety. Once a multi-dose vial of measles vaccine becomes contaminated (e.g., if the same contaminated needle and syringe are used to reconstitute successive vials), pathogens will grow quickly if the temperature of the vial is not cold. Thermal shock to the vaccine and death to the unfortunate vaccinee have been documented in many countries from just this sort of scenario occurring during the less demanding routine services. Robert ___________________________________________________________ Quoted from “Thermostability of vaccinesâ€