Historically, the whooping cough vaccine has been administered as a merthiolate-killed bacterial cell suspension which is part of the DTP vaccine (The P in DTP stands for Pertussis cells). Unfortunately, about 20% of the children that receive the whole cell vaccine experience mild side effects. About 0.1% of infants experience convulsions soon after receiving the vaccine and in a very small number of cases (1 in 150,000?) severe or irreversible brain damage may occur. In the absence of the disease in an immune population, parents have begun to wonder if the risk of vaccinating children outweighs the risk of the disease, and the value of the whole cell vaccine has been questioned.

Several new acellular vaccines have been developed from purified components of B. pertussis. Demonstration of the protective effects of anti-PTx and anti-FHA antibodies in the mouse model, focused vaccine production on combinations of inactivated pertussis toxin (toxoid) and filamentous hemagglutinin. Multicomponent acellular vaccines containing combinations of pertussis toxoid, filamentous hemagglutinin, pertactin, and the two types of fimbriae, are now being used in several countries including the U.S. The new vaccine, known as acellular pertussis has fewer side effects than the whole cell vaccine and is currently recommended for use under the conditions described below.

For decades, the pertussis vaccine has been given in combination with vaccines against diphtheria and tetanus. The combination is known as the DTP vaccine. Recently, infants have been able to receive a vaccine that combines the DTP vaccine with the vaccine against Haemophilus influenzae type b meningitis (Hib). This vaccine is called DTPH. The diphtheria-tetanus-pertussis vaccine using acellular pertussis is known as DTaP. The diphtheria-tetanus-pertussis vaccination is given in five doses: at 2, 4, 6, 12-18 months and 4-6 years of age. Previously, DTaP had been recommended only for the fourth and fifth doses. Following FDA licensure of DTaP for infants, the Advisory Committee on Immunization Practices of the United States Public Health Service now recommends that DTaP be used for the first four doses and that DTaP still be used for the fourth and fifth doses for children who received DTP in their first three doses. The Committee is awaiting study results before making a recommendation for the fifth dose for children who now will receive DTaP in their first four doses. The recommendation still permits the use of DTP and DTPH--the combination that includes the vaccine against Haemophilus influenzae type b meningitis.

Whooping Cough In Wisconsin 2004

There were more than 4,800 cases of whooping cough were reported in Wisconsin in 2004, an increase of more than 690 percent over the previoust year, when there were 716. In the mid-1980s, when whooping cough outbreaks were considered particularly bad, there were 400 to 500 reported cases per year.

Dane County reported over 150 cases. The Public Health Department of the City of Madison saw over 100 cases in 2004, even though the disease is undoubtedly under-reported. The University Health Services saw a rise in incidence on the UW campus. Last semester UHS confirmed several student cases each week, with several additional unconfirmed occurrences.

Since the development of the pertussis vaccine, the incidence of whooping cough in the U.S. steadily declined until the past two decades when it began to rise. According to the Center for Disease Control, Wisconsin currently ranks second in the nation for disease incidence rate at 27.7 cases per 100,000 individuals.

It is difficult to draw conclusions by comparing the 2004 outbreak with those in past years. The increase in whooping cough numbers can partially be explained by new testing procedures that became available last year. The new test is quicker and more sensitive than previous tests, and physicians are putting more emphasis on diagnosing the illness.

Also, whooping cough infections tend to run on a 2-5 year cycle, and 2004 could be a high point in the cycle.

Like flu viruses, the bacterium is highly contagious and tends to pass quickly from person to person through coughing and sneezing. If increasing numbers of individuals have the illness, then the risk of infection increases in the general population.

Many young children are vaccinated against whooping cough with the pertussis vaccine. However, the vaccine is only approved for children under seven years of age. Antibody-mediated immunity wanes in approximately ten years, leaving older individuals more susceptible to the disease. Adults get infected, often to a lesser degree, but they are still able to spread the disease to unimmunized children.

For more information on whooping cough, see the CDC listings under pertussis.

whooping cough Pertussis - Technical Information
vaccine: http://www.cdc.gov/nip/publications/VIS/vis-dtp.pdf.