Control of pertussis in the world

Abstract

Available data indicate that pertussis remains an important disease during infancy and childhood, particularly among those who are inadequately immunized. Over the past 15 years, successful immunization programmes have been implemented in most countries in the world. Some problems have arisen in the industrialized world where pertussis had been well controlled previously. The underlying causes of these problems are apathy and complacency on the part of physicians and parents, negative attitudes to immunization spread by anti-immunization pressure groups and litigation over liability for alleged vaccine-related injures. In developing countries, immunization coverage with primary series of three doses of DPT vaccine in infants exceeds 80%, but there are considerable differences in coverage rates between regions and between and within countries. Failures to reach and maintain high immunization coverage in developing countries are caused by multiple factors including weak management of immunization services, missing opportunities to immunize eligible children and ineffective information and motivation of mothers to return to complete the immunization series. To effectively control pertussis in the world, all countries should use available pertussis vaccines in immunization programmes for children. Since acellular pertussis vaccines are not generally available, the widespread use of DPT vaccine containing the whole-cell pertussis component should be continued. All efforts should be directed to increase or maintain high immunization coverage with DPT immunization at the level of at least 90% in all districts. Surveillance of pertussis morbidity should be strengthened in all countries and ideally, pertussis should be a reportable disease. More information on the present epidemiological pattern of pertussis, especially age distribution of pertussis cases in developing countries, is needed to develop the policy of booster doses of DPT vaccine in children > 1 year.

PIP: Pertussis remains an important disease during infancy and childhood, particularly among those who are inadequately immunized. Over the past 15 years, successful immunization programs have been implemented in most countries in the world. Some problems have arisen in the industrialized world, where pertussis had been well controlled previously, because of complacency of physicians and parents, negative attitudes to immunization, and liability for alleged vaccine-related injuries. In developing countries, immunization coverage, with primary series of 3 doses of DPT vaccine in infants, exceeds 80%. In the late 1970s and the 1980s, European countries reported an incidence rate between 10 and 100 per 100 000 (Sweden and Italy). In Germany the incidence rate was above 20/100,000. In the former USSR, the incidence rate during 1988-1991 ranged from 17 to 24/100,000 population. In the United States in the 1970s and the beginning of the 1980s the number of reported cases ranged between 1000 and 2000, with the incidence rate between 0.5 and 1/100,000 population. Experience in Japan, the United Kingdom and Sweden has demonstrated that stopping vaccination with pertussis vaccine or a decline of pertussis vaccine coverage in a previously highly vaccinated population resulted in resurgence of the disease. Several countries in Africa reported incidence rates above 100/100,000 population (Angola, Liberia, Malawi) and many countries reported incidence rates between 10 and 100/100,000 population. In the developing world, the main problem is the high drop-out rates between the first and the third dose of DPT vaccine. Japanese acellular pertussis vaccines are safe and up to 80% effective in preventing clinically significant pertussis. Efforts should be exerted to increase or maintain high immunization coverage with DPT immunization at the level of at least 90% in all countries.