About thermal assault

The most authoritative reference on this subject is a WHO publication Temperature sensitivity of vaccines and can be used as a reference to answer several of your questions: 1. Thermal Assault: this idea has floated around for 30 years, applied to several practices that involve changing the temperature of vaccine in the process of reconstitution. It is not mentioned in the WHO guide and I have not seen the phenomenon confirmed in the literature. 2. The following practices that you mention may be policy in India but are not part of the drafting of global policy: a. “Diluent cooled for more than a day before reconstitution”; diluent needs to be between +2 and +8C at the time of reconstitution but no advance cooling is required b. “OPV to be kept at ambient during administration, one vial at a time”; no basis for this in the guide; OPV needs to be kept at +2 to +8C during administration unless ‘beyond the cold chain procedures’ are national policy. c. “Discard liquid vaccine vials regardless of the VVM after 3 ‘beyond the cold chain’ events”; no guidance in the guide but WHO policies in this area are under development 3. The technique of keeping opened vials cool during the session in perforated sponge lid inserts that you mention is not mentioned in the Guide but is widely supported in WHO training material and field documents and was demonstrated two decades ago in field studies. 4. Taking vaccine out of the refrigerator (ILR or domestic types) or cold box and returning vials to cooling after using a vial has no negative effect on vaccine potency documented in my knowledge, except that repeated freezing events cause accumulative damage to certain vaccines. 5. Freeze prevention of certain vaccines is very well documented in the Guide and is covered by many documents detailing the results of field and laboratory testing. I would suggest that accidental freezing is the ONLY condition of thermal shock that can cause rapid deterioration in vaccine potency. John Lloyd Immunization Logistics Consultant [email protected] 10 chemin du Mont Blanc 01210 Ferney Voltaire France +33 674 932914

Thank you sir.

I would like to affirm John Lloyd’s suggestion to use WHO’s Temperature sensitivity of vaccines as a reference. Furthermore, PATH has recently mapped out stability data of licensed vaccines and this is also a useful guide and should be available on Technet resources. Stability-table-LICENSED-FINAL-updated-8212012.pdf To complement John’s statements below: • ]WHO knows of no body of scientific evidence to assert the phenomena of ‘thermal assault’ on vaccines as queried in this posting • Standard WHO recommendations have always been that the diluent, if not stored in the cold chain at +2ºC - +8ºC, should be cooled to that temperature range for several hours prior to use for reconstitution -- preferably for 24 hours or for a period of time sufficient to ensure that the vaccine and diluent are both at temperatures between+2ºC - +8ºC when they are reconstituted . This was because some of the vaccines to be reconstituted, especially live attenuated virus vaccines, were not heat stable and in fact had only a limited stability when reconstituted, even when kept at +2ºC - +8ºC. Current formulations of these types of vaccines, but not all, are more stable than in previous years. Vaccinators are advised to follow manufacturer’s instructions regarding cooling prior to reconstitution. • Reconstituted vaccines may become contaminated with staphylococcus and other organisms from improper handling. To avoid this, in line with the Multi-dose Vial Policy, reconstituted vaccines must be kept cooled and must be discarded at the end of the immunization session, or within six hours after opening, whichever comes first. • At service delivery level, it is recommended that most vaccines be kept at between +2ºC to +8ºC. The VVM (if it is attached) indicates whether the individual vial has been exposed to cumulative levels of heat over time such that the vaccine’s potency may be compromised and thus its stability diminished. This means that vaccines can be used reliably if the VVM has not passed its discard point, even if there have been short breaks in the cold chain, and provided that the expiry date has not passed. It is therefore not dependent on how many times the vial is taken out of the chain. However, it is important to note that current VVMs do not necessarily reflect short ‘peak’ exposures of vaccines to extremely high temperatures (i.e., 45ºC or above). Care should be taken to avoid these situations, especially during transport. • WHO offers a range of video resources available that explain how VVMs work and how to interpret them properly. I have listed them at the end of the posting. • WHO recommends the use of baskets in ILRs to address the concerns as mentioned in the post, and encourages the use of continuous temperature monitoring devices (digital) to adequately monitor excursions outside the recommended temperature ranges • The global guidance on the Multi-Dose Vial Policy and the Immunization in Practice modules are currently being revised by WHO and will be issued this later year. Diana Chang Blanc Team Manager, Programme Operations WHO Geneva, EPI How does a VVM work? by Denis Maire https://vimeo.com/58747176 Denis Maire summarizes the technical characteristics of VVMs and explains how they work. Interpretation of VVM in relation to other temperature monitoring devices by Umit Kartoglu https://vimeo.com/58156915 Umit Kartoglu reviews temperature monitoring devices used in a typical vaccine cold chain and analyses how the readings relate to each other when there are more than one device at a particular point. This analysis is done from the VVM perspective. Using VVM as a stock management tool by Umit Kartoglu https://vimeo.com/58161022 Umit Kartoglu Umit Kartoglu reviews the requirements for product arrival, storage and dispatch and analyses the role of VVM in effective stock management for each step. Special emphasis is given to the relation of VVM and expiry date in illustrating how VVM over-rules earliest expiry first out principle. Vaccines beyond the cold chain by Simona Zipursky https://vimeo.com/58148555 Simona Zipursky reviews the studies on taking vaccines beyond the cold chain all published in peer-review journals and comments on how VVMs could be instrumental in these operations. VVMs getting smarter by Umit Kartoglu https://vimeo.com/58161023 Umit Kartoglu reviews the recent changes in integrity and location of VVMs and the new message VVM is giving whether a vial containing multi-dose vaccine following opening can be kept for a subsequent session or not. VVM use at the most periphery by Serge Ganivet https://vimeo.com/58680045 Serge Ganivet reviews the VVM use at the most periphery through different examples and brings new perspectives on how to make best decisions based on the expiry and VVM readings.

Please Note: PATH has since updated their chart on vaccine stability. I am attaching the updated version here. Please also find it available at their website: http://www.path.org/publications/detail.php?i=1696 Stability-table-LICENSED-FINAL-updated-11-25-2013.pdf