Although certain antibiotics such as erythromycin destroy B. pertussis bacteria, there is a short window of time after infection in which antibiotics are effective. Once whooping cough symptoms are present, severe coughing fits can persist for months because most B. pertussis pathology results not from the bacteria itself, but from the variety of toxins it produces and secretes. In many cases, by the time antibiotics are prescribed, it’s too late -- biologically active toxins have already been released and are causing pathology. In addition, antibiotics don’t necessarily kill 100% of bacteria in a host, particularly when the organisms are living in more poorly vascularized tissues.
Due to the difficulty in treating symptomatic pertussis and its potentially lethal outcomes, vaccines were developed as preventative medicines, inducing the immune system to produce protective antibodies against B. pertussis infection. Whole cell pertussis (wP) vaccines composed of killed whole B. pertussis were introduced in the 1940’s and were combined with diphtheria and tetanus to create DPT vaccines. Although widespread vaccination with wP reduced pertussis rates in the U.S. to a low of roughly 1,000 cases by 1976, concerns about safety led the U.S. and other developed countries to introduce acellular pertussis (aP) vaccines in the 1990’s. aP vaccines are composed of a few antigens from B. pertussis and do not include the bacteria itself, and are also combined with diphtheria and tetanus to form DTaP for children and Tdap for adults and adolescents. Over the last three decades, evidence suggests that aP vaccines are less potent and have shorter durability than wP vaccines. Still, the safety profile of wP is not acceptable to more affluent countries that can afford more expensive aP vaccines. As a result, in developed nations, to compensate for lower potency, public health agencies have recommended an increasing number of childhood aP boosters to address increasing rates of pertussis.