Problems and progress in immunization

Advances in immunology, microbial genetics, molecular biology and biochemistry are opening prospects for new purified and synthetic antigens against infectious diseases, cancers of viral origin and some immunodeficiencies. Immunization programmes against major childhood diseases with commonly used vaccines gave excellent results and are leading to their virtual eradication in developed countries. However some vaccines like the one against pertussis proved to be of considerably lower effectiveness. Results achieved in developing countries are in general lagging behind due to lower immunization coverage. While in some countries immunization strategies for eradication of measles are discussed, in others it is questionable whether immunization should continue due to failures of immunization programmes. Evaluation of the effectiveness of national immunization programmes by surveillance and various other methods including the use of epidemiological models point ot the deficiencies of vaccine potency and/or stability and the inadequacy of vaccination schemes and coverages. There is a need to determine optimal immunization programmes for control and possible eradication with currently available antigens and new ones. For newly developed vaccines, ever increasing in number, but with the uncertainty of their appropriate public health use, it is essential to study their optimal and most cost-effective uses e.g., pertussis vaccination is an old unsolved problem and that against hepatitis B a new one. Better results can be obtained with current vaccines by appropriate modification of immunization programmes. Some of the proposed strategies for using recently developed vaccines are questionable and need critical examination.(ABSTRACT TRUNCATED AT 250 WORDS)