face in line with the facial nerve and orbits (Weinstein, 1973). Considered a form of localized tetanus, incubation is complete in 1 to 2 days after the initial insult, which is most often a head wound (Weinstein, 1973).

Following the widespread use of tetanus toxoid–containing vaccines, tetanus infections have become an uncommon occurrence in the United States. In 1947, the incidence of reported cases was 0.39 per 100,000 in the United States (Wassilak et al., 2008). This number dropped dramatically, and from 1998 to 2000, the average incidence was approximately 0.16 cases per 1,000,000 representing a 96 percent decrease in the incidence rate (CDC, 2003).

Tetanus infections peak in midsummer and are more common in warm, damp climates. This is likely due to soil conditions and increased exposure to spores as well as increased injuries that occur during the summer months (Axnick and Alexander, 1957; Bytchenko, 1966; Heath et al., 1964; LaForce et al., 1969).

Although described by the ancient Egyptians and Greeks, the origin of tetanus disease was not described until 1884 when Carle and Rattone showed that tetanus symptoms could be induced in rabbits when inoculated with pustular fluid from a fatal case of human tetanus (Wassilak et al., 2008). In the late 1800s, C. tetani spores were shown to survive heating and germinate in anaerobic environments, and the repeated inoculation with small quantities of toxin led to antibody production that was able to neutralize the effects of tetanus toxin (Wassilak et al., 2008). In 1924, the tetanus toxoid created by chemically inactivating the tetanus toxin was shown to induce active immunity to tetanus disease prior to exposure to the pathogen (Wassilak et al., 2008).

Currently, commercial tetanus toxoid is produced by culturing C. tet-ani in liquid medium and transforming the purified toxin with 40 percent formaldehyde at 37°C (Wassilak et al., 2008). In the United States, tetanus toxoid vaccines are available as a single tetanus toxoid vaccine (TT) (Sanofi Pasteur) and in combination with diphtheria toxoid as DT/Td, acellular pertussis as DTaP/Tdap, and as DTaP with other antigens such as Haemophilus influenzae B (HiB) conjugate (Wassilak et al., 2008).

Pertussis Antigen

Pertussis (whooping cough) is an upper respiratory infection caused by Bordetella pertussis, a gram-negative, pleomorphic bacillus that attaches to cells lining the respiratory tract (Edwards and Decker, 2008). B. pertussis is not a particularly invasive bacterium and typically does not penetrate sub-mucosal cells or the bloodstream, although toxins secreted by the bacteria may produce systemic effects (Edwards and Decker, 2008).

The National Academies of Sciences, Engineering, and Medicine
500 Fifth St. N.W. | Washington, D.C. 20001

Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement