Improving the heat stability of vaccines: problems, needs, and approaches.

Biologics comprise temperature-sensitive organic polymers that must retain their primary and secondary structures as well as their interrelationships if their activities are to be retained. Targets for temperature-stable vaccines assume a technologic database that exceeds present knowledge. For this reason, new territory must be explored. Coupled with lack of scientific information is lack of economic incentive for the producer to undertake new areas of basic research on stabilization. Moreover, the means of protecting and rewarding the inventor are extremely weak, and no source of funds for meeting the costs is evident. It is critical, at this time, to weigh the costs of improving vaccine against those of establishing an effective cold chain. Developing a cold chain seems the more likely choice.