If the vaccine has a vaccine vial monitor (VVM), cool water-packs can be used for transport between the primary store and the health facility for any vaccine EXCEPT those with a VVM 2 or VVM 7. This includes the oral poliovirus vaccine (OPV), some brands of inactivated poliovirus vaccine (IPV) and varicella vaccine. When transporting vaccines for outreach purposes, cool water-packs can be used for ALL vaccines that carry a VVM.

For short journeys in sub-zero temperatures, cool water-packs will protect both liquid freeze-sensitive vaccines and vaccine diluents against the risk of freezing. They can safely be used for this purpose even when the vaccine does not have a VVM.

Use passive containers with a published cool life at least as long as the longest planned transport leg, measured from the time of packing the container in the supplying store to the time of unpacking in the receiving store. It is important to allow a good safety margin to cover unexpected events such as transport delays and variations in cool water-pack temperature.

Warm water-packs

For long journeys in sub-zero temperatures, warm water-packs are needed to prevent most liquid freeze-sensitive vaccines and vaccine diluents from freezing, provided the vaccines have VVMs. However, warm water-packs should NEVER be used to transport OPV, IPV with VVM 7, varicella or any other highly heat-sensitive vaccine. They should also NEVER be used for any vaccine without a VVM because there is no way to monitor the effect of exposure to temperatures above the labelled storage range of +2°C to +8°C.

Passive containers should have a rated warm life at least as long as that required for the longest planned transport leg, measured from the time of packing the container in the supplying store to the time of unpacking in the receiving store. Once again, it is important to ensure a good safety margin to cover eventualities such as transport delays and variations in warm water-pack temperature at the time of packing.

Transporting vaccines without VVMs

For vaccines that are NOT supplied with VVMs, the following principles for choosing coolant-packs apply:

•       In warm and hot climates, cool water-packs should NOT be used for routine vaccine transport because cumulative heat exposure to temperatures above +8°C cannot be monitored adequately.

•     In cold climates, use cool water-packs to protect freeze-sensitive vaccines or lyophilized vaccines bundled with diluent from exposure to sub-zero conditions. Warm water-packs should NEVER be used for this purpose because of the risk of prolonged exposure to temperatures above +8°C.

•       RotaTeq® should only be transported using conditioned icepacks; its freeze-sensitivity status is not fully established and a suitable VVM is currently not available for this vaccine. In addition, its maximum allowable exposure time at temperatures above +8°C is only 48 hours at +9°C to +25°C. It is highly likely that temperatures above +8°C will occur when cool water-packs are used in hot climates. Since there are usually two or three transport legs between the national store and the health facility, it is possible that this 48-hour exposure period could be exceeded, unless all the journey times are very short.

Outreach recommendations are the same as for vaccines with VVMs (see previous section “Vaccine distribution guidelines”) because of the relatively short transport times involved.

Refrigerants and foaming agents

Refrigerants

Refrigerants made with chlorofluorocarbon (CFC) or hydrochlorofluorocarbon (HCFC) are potent ozone depleting substances with extremely high global warming potential (GWP) ratings. Due to their ozone depleting impact they were scheduled to be phased out under the regulatory regime of the Montreal Protocol. CFCs were phased out in 1996 in industrialized countries and 2010 in low and middle-income countries (LMICs). HCFCs are to be 100% phased-out in industrialized countries by 2020, and in LMICs by 2030.

Hydrofluorocarbon (HFC) has been used as a substitute for CFCs and HCFCs. HFCs do not impact the ozone layer but have far greater GWP than the basic standard carbon dioxide (CO₂) with GWP of 1.

Natural refrigerants, such as hydrocarbons, CO₂ and ammonia are increasingly used in domestic and commercial refrigeration. They are low GWP substances with a GWP of less than 3 for hydrocarbons, 1 for CO₂ and 0 for ammonia.

R12, a CFC, was commonly replaced with HFC (e.g. R134a). An increasing number of manufacturers are now using the hydrocarbon R600a (isobutene). Cold room and freezer room manufactures may use a variety of other refrigerants. Until 2010, developing country manufacturers were still allowed to use CFC refrigerants, but many of them had already made the change to more environmentally-benign gases.

PQS performance specifications permit the use of hydrocarbon (e.g. R600a) and are phasing out HFC refrigerants in refrigerators and freezers. Existing appliances with HFC refrigerants including R134a will be phased out in 2020. Hydrocarbons are still not permitted for cold rooms and freezer rooms.

The table below gives the Ozone Depletion Potential (ODP) and Global Warming Potential (GWP) figures for the gases described above and in the next section. Equipment which uses cyclopentane foamed insulation and the refrigerant R600 is currently the best environmental choice. However, it is flammable and must be handled with care.

ODP and GWP figures for some key gases