Vaccines must be continuously kept cold during all aspects of storage, transportation and use. This cold storage system is called a cold chain system.

Since vaccines are temperature sensitive, every link from the vaccine manufacturing department to the site where the vaccine is used may fail due to excessive temperature.

In order to ensure that the vaccines used in planned immunization have proper refrigeration equipment throughout the entire process from production, storage, transportation, distribution to use, so that the vaccines are always placed in the prescribed cold storage state and the reasonable potency of the vaccines is not compromised, our country

Established a cold chain cooperation project with UNICEF.

By the end of 1989, 95% of counties (districts) in 30 provinces, municipalities, and autonomous regions across the country had basically completed cold chain equipment.

The supporting equipment of the cold chain includes low-temperature cold storage for storing vaccines, ice freezers, ordinary cold storage, special refrigerated trucks for transporting vaccines, vaccine transport trucks, refrigerators, refrigerated boxes, refrigerated backpacks, computers and spare parts, etc.