Medical study finds many older Americans lacking immunity to tetanus

March 23, 1995|By Medical Tribune News Service

Despite the availability of effective vaccines for tetanus since the 1940s, high numbers of older Americans are not properly immunized against the now-rare but often fatal infectious disease, according to a new study.

Researchers hope the findings will spur doctors to give tetanus booster shots every 10 years to their elderly patients.

Scientists from the National Institutes of Health in Bethesda and the Centers for Disease Control and Prevention in Atlanta measured tetanus antibody levels in 10,618 Americans to assess their immune status.

They found that while about 88 percent of children ages 6 to 11 had enough antibodies to protect them from tetanus (children are required to be vaccinated before attending school), the rates steadily decreased with age.

Among those 70 or older, only 28 percent were sufficiently protected, the researchers reported in today's New England Journal of Medicine.

The number of cases of tetanus in the United States has remained relatively stable, an estimated 120 to 240 cases each year.

Of those, 59 percent occur in people 60 or older, a Texas researcher wrote in an accompanying editorial.

Tetanus is a deadly infection caused by a microbe usually found in the top layer of soil. The most common route of transmission is through puncture wounds or cuts.

The disease targets the central nervous system, causing severe muscle spasms, such as lockjaw, and death.

By World War II, tetanus had largely been eliminated with the use of effective vaccines. However, a small, steady number of cases persist in the United States.

Most cases occur among adults who are unvaccinated or whose history of vaccination is unknown, the scientists said.

According to lead researcher Dr. Peter Gergen of the NIH, "administering a primary series of tetanus vaccinations to elderly persons may offer the best means of rapidly decreasing" these remaining cases.

Dr. Jay Sanford of the University of Texas Southwestern Medical Center in Dallas recommended periodic booster shots. "Physicians would be wise to remember that a booster in time -- every 10 years -- prevents tetanus," he wrote in an editorial accompanying the new study.

According to Dr. Thomas Cate of the infectious diseases division at Baylor College of Medicine in Houston, the low number of tetanus cases is a credit to the effectiveness of the vaccine -- which in most elderly people was administered 40 or 50 years ago.

"You get a vaccination series as a young kid, and then most people forget about tetanus," Dr. Cate said, adding that poor recordkeeping and a lack of awareness on the part of doctors have kept the elderly from maintaining immunity to tetanus.

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