Vaccine and Pharmaceutical Supply Systems and Equipment

Cold chain innovations

Protecting health care products from damaging temperatures

Keeping perishable vaccines at a specific temperature range (e.g., 2°C to 8°C) as they travel from manufacturer to beneficiary is vital for immunization programs—and extremely challenging, especially in low-resource settings. Unreliable electricity, poorly maintained equipment, and long distances between health care facilities can compromise temperature control efforts, exposing vaccines to unsuitable temperatures that negatively impact potency. Overheating and accidental freezing can result in vaccine wastage (when vaccines are discarded due to suspected damage) or the inadvertent administration of subpotent vaccine, which increases the risk that beneficiaries are not fully protected from disease.

A weak cold chain limits how far a vaccine can be effectively transported and therefore how many people can access the lifesaving intervention. In collaboration with numerous partners and technical collaborators, PATH actively develops and facilitates access to innovative technology solutions, policies, and programs that help developing countries store, monitor, and transport vaccines at appropriate temperatures, even in hot climates with little to no electricity. Notable innovations have included:

  • Solar direct-drive refrigerators. Solar energy is a promising solution for powering the storage and transportation needs of vaccines and heat-sensitive drugs at controlled temperatures. Solar direct-drive refrigerators represent a second-generation of solar refrigerators. Instead of storing electrical energy in a battery, the refrigerators use cool storage (i.e., an ice battery) to maintain appropriate temperatures. Visit our page on solar direct-drive refrigerators to learn more »
  • Domestic refrigeration equipment. Many countries including the United States have health facilities that use food refrigerators that do not meet WHO prequalification standards for storing vaccines, putting valuable health care products at risk of exposure to freezing temperatures as well as rapid warm-up after power cuts. PATH has identified specific modifications that can be made to domestic refrigerators to increase their reliability and performance for vaccine storage. Visit our page on domestic refrigeration equipment to learn more »
  • Innovations in transport. To protect vaccines and essential medicines from temperature extremes during international and in-country transport, PATH has worked with a variety of manufacturers to develop a range of cooling and insulation materials that help to mitigate the effects of temperature excursions. Visit our page on innovations in transport to learn more »
  • Temperature monitoring. The tracking and regulation of temperatures is critical for assessing vaccine handling quality, detecting malfunctioning equipment, and preventing temperature fluctuations that can negatively impact vaccine potency and safety. Various temperature monitoring technologies now exist to better record and manage cold chain performance. Visit our page on temperature monitoring to learn more »
  • Controlled temperature chain. Certain vaccines are much more heat stable than what is indicated on their vial labels. A controlled temperature chain is an approach being explored for the distribution of some heat-stable vaccines to remote and difficult-to-access areas for limited periods of time (e.g., one to four days), when access to refrigeration and ice is extremely limited. Visit our page on controlled temperature chain to learn more »

From advancing new health technologies to strengthening systems, PATH is working to ensure that vaccines and other health care products arrive at the right place, at the right time, and in the right condition.