During the 1900s the first epidemic of pertussis was noticed. It was a very common childhood illness. High rates of deaths were due to pertussis which is an acute infection of the respiratory tract. It was especially a serious disease in targeting infants due to their underdeveloped bodies. Around the 1940s a vaccination to prevent deaths caused by pertussis was invented and the rate of deaths lowered dramatically. However, recent cases of pertussis have been on the rise, and not only is it affecting infants and small children it is occuring in people who have been vaccinated and are ten years of age or older.
When the first pertussis vaccine became available it was a whole-cell pertussis vaccine and was developed in the 1940s. It was in widespread use by the 1980s the average incidence of pertussis had decreased to about 1/100,000 as compared to 150/100,000 during the 1920s throught the 40s. Now the pertussis vaccine is combined with diphtheria toxoid and tetanus toxoid to make the vaccination DTaP. The pertussis component of this vaccine is a more purified "acellular" version, which produces fewer side effects. In 2005, two new tetanus toxoid-diphtheria-acellular pertussis (Tdap) vaccines were licensed. These vaccines are the first acellular pertussis-containing vaccines that make it possible to vaccinate adolescents and adults against pertussis in contrast to Dtap which is for infants and young children.
Both DTaP and Tdap vaccines are "inactivated" vaccines. Inactivated vaccines do not contain live bacteria or virus and cannot reproduce, which is why multiple doses are needed to produce immunity. DTaP is for children younger than 7 years and has a higher concentration of pertussis than Tdap, which is intended for persons 10 years and older. All infants should receive DTaP vaccine as part of their routine immunization unless they have a medical reason not to.