Capacity of Vaccine Carriers and Cold Boxes

Dear Carla, You can find the definition of vaccine storage capacity in the PQS specifications: http://www.who.int/immunization_standards/vaccine_quality/pqs_e04_insulated_containers/en/index.html Vaccine carrier: Vaccine storage capacity: The total volume of the vaccine storage compartment, in litres. The measurement is equal to the volume of the largest rectilinear object that can be inserted into the compartment with all the manufacturer's specified packs in place. Cold boxes: Vaccine storage capacity: The vaccine storage compartment is loaded with cardboard boxes or blocks made out of plastic foam or wood measuring 100x100x100 mm or 100x100x50 mm, packed so that there is minimal air space between each column of packets or between the units and the ice-pack lining. The total volume of the test units, in litres, represents the net volume available for the storage of vaccines. Denis Maire WHO PQS Secretariat

The number of vials a vaccine carrier or cold box can hold depends on individual vaccine volume per dose and the way how vaccines are kept in the cold box or carrier ( a single vaccine or combination) For the same vaccines # doses = Net capacity of equipment/ volume per dose For different vaccines # of doses= Sum of (the same vaccine combination), finding through optimization Filed practices: Vaccine carriers and cold boxes are used to transport different vaccines for transportation or storage or vaccination sessions. So, the first thing you need to do is just to list the vaccine types and presentation that are currently in use in a particular country. Then, based on the vaccine type and presentation you can easily determine volume per dose using a standard table listing all available vaccines (WHO prequalified). Once you have each volume, then it is a matter calculation: Two combination options to transport vaccines: One type of vaccine or combination of more than one. Example: If you want to know how much OPV (20 doses per vial) can be transported using a 2L vaccine carrier. From the table, one can find the volume to be 1cm3 per dose. Then you need to divide the net capacity by this value and you get about 2000 doses of OPV or 100 vials of OPV. What about if you have multiple vaccines? You have to find the number for each vaccine in the box. The easiest way in the field is the session target for each vaccine gives best guidance. For exercise purposes, you could play around by combining different options to come up with the optimal size. If you need the reference table for the volume per dose, let me know.