Although state health departments now rarely report diphtheria in the United States, the disease was one of the most common causes of illness and death among children before a vaccine was available. Since the introduction of diphtheria vaccines, which began in the 1920s and 1930s, and implementation of universal childhood immunization in the late 1940s, diphtheria has been well-controlled in the United States.
The Council of State and Territorial Epidemiologists revised the following case definition for diphtheria and published it in 2010.
Probable: In the absence of a more likely diagnosis, an upper respiratory tract illness with an adherent membrane of the nose, pharynx, tonsils, or larynx; and absence of laboratory confirmation; and lack of epidemiologic linkage to a laboratory-confirmed case of diphtheria.
Confirmed: An upper respiratory tract illness with an adherent membrane of the nose, pharynx, tonsils, or larynx; and any of the following: isolation of Corynebacterium diphtheriae from the nose or throat; or histopathologic diagnosis of diphtheria; or epidemiologic linkage to a laboratory-confirmed case of diphtheria.
Comment: Cutaneous diphtheria should not be reported. Respiratory disease caused by nontoxigenic C. diphtheriae should be reported as diphtheria. All diphtheria isolates, regardless of association with disease, should be sent to the Diphtheria Laboratory, National Center for Immunization and Respiratory Diseases (NCIRD), CDC.
Healthcare professionals should promptly report suspected diphtheria cases to their respective health department and then the CDC Emergency Operations Center (770-488-7100) to obtain diphtheria antitoxin for treating the patient. An FDA-licensed diphtheria antitoxin product is no longer available commercially in the United States. However, diphtheria antitoxin is available from CDC under an Investigational New Drug (IND) protocol. Healthcare professionals must provide additional epidemiologic and clinical data to receive diphtheria antitoxin under the IND.
Healthcare professionals should notify their state health department promptly so they can promptly initiate an epidemiologic investigation. The state health department is responsible for reporting probable and confirmed cases to the National Notifiable Diseases Surveillance System. Health departments should not delay reporting because of incomplete information or lack of laboratory confirmation.