Vaccine stability in the context of vaccine delivery in a developing country: India

Infant immunisation coverages of 80-85% have become sustainable throughout the developing world. The vaccine market is enormous in developing countries; in 1992, the total consumption of vaccine doses amounted to 2207 millions. There were only 127 million births, and the actual doses given to infants would have been fewer than 1000 million. This indicates huge wastage, which could be saved if vaccines were more stable at high temperatures and did not become contaminated. The vaccine delivery problems are compounded by the rural residence of the majority of the population and by the reliance on village health workers who are not the optimum health care providers. Under these circumstances, post-marketing epidemiological surveillance of vaccine-preventable diseases is absolutely necessary to monitor vaccine performance which is a function of the efficacy of the products and their potency when delivered.