If you believe the experts only 60% of American adults have adequate immunization to ward off diphtheria infections and 72% are protected against tetanus.

Tetanus is a sometimes-fatal illness caused by toxin-producing bacteria that usually takes hold in a cut or wound. The disease is characterized by painful muscle spasms or contractions.

Diphtheria is caused by another type of bacteria that primarily attack the larynx, tonsils and throat. The toxin produced by the bug can damage the nerves and heart.

While most US children receive immunization for diphtheria and tetanus, many adults may not realize that over time the protection provided by the shots can wane.

In the study, 18,045 people aged 6 years and older were tested for the presence of diphtheria and tetanus antibodies in their blood between 1988 and 1994.

The researchers found that 91% of children aged 6 to 11 years were found to have protective levels of diphtheria and tetanus antibodies. However, the number of adults found to have protective levels was another story altogether.

Overall, only about 50% of adults had protective antibodies to both diseases, and among those 70 years and older, only about 30% had protective levels against either of the two illnesses.

Although diphtheria and tetanus occur only rarely in the US, a recent outbreak of diphtheria in the former Soviet Union is a reminder that even a well-controlled infection can re-emerge when population immunity is not maintained.

Since immunity to diphtheria and tetanus decreases with age, doctors should re-immunize patients at 11 to 12 years of age and every 10 years thereafter, as recommended by the US Advisory Committee on Immunization Practices.

Reuters May 6, 2002

Annals of Internal Medicine May 7, 2002;136:660-666