Acellular pertussis vaccines: a turning point in infant and adolescent vaccination.

Whooping cough, an infectious disease caused by the gram-negative bacterium Bordetella pertussis, is a life-threatening disease that cannot be controlled by antibiotic treatment or other procedures of modern medicine. Immunization, using a vaccine made of heat-killed bacteria, has been the only way to prevent the disease and keep the infection under control. However, the high reactogenicity of the whole-cell vaccine available so far has made vaccination very controversial, and vaccine use has been restricted to the minimum doses strictly necessary to protect infants during the first few years of life, when the disease is most dangerous. This policy left unsolved the problem of controlling the circulation of the pathogens that are still spreading undisturbed in the population, even after decades of vaccine use. Today, the introduction of acellular vaccines that are efficacious and virtually free of side effects suggests that the new vaccines can be used safely to immunize not only infants, toddlers, and preschool children, but also adolescents and adults, making possible the complete control of the disease and infection, so that policies addressing the eradication of the disease become feasible. The absence of constraints for the use of pertussis vaccine will allow the rational design of the optimal combinations of vaccines for each age.