June 13, 1997

VUMC researchers work to wipe out whooping cough

VUMC researchers work to wipe out whooping cough

reporter_6.13.97_2.jpg (20k)

Pertussis doesn't just strike children. Vanderbilt student Jeanette Bederman recently suffered through a bout of the disease, also known as whooping cough

When Vanderbilt University sophomore Jeanette Bederman started coughing last September, she passed it off as a sinus infection.

When the cough worsened, was accompanied by vomiting, and persisted well into October, Bederman saw a doctor who, in collaboration with doctors in Pediatric Infectious Diseases, made the diagnosis ‹ she had pertussis, commonly known as whooping cough or the one hundred day cough.

In her case, it was actually more than 100 days. The cough hung on through the middle of January.

"I couldn't sleep because of the cough, and I was so tired every day," said Bederman, an ROTC student. "I had to prioritize what was most important. I didn't have much energy to do anything," she said.

Vanderbilt University Medical Center has been heavily involved in research on pertussis, an infectious disease most commonly found in children. The disease also occurs in adults who were immunized as children, like Bederman.

The disease is characterized by violent bouts of coughing that persist until the breath is exhausted and respiration becomes noisy, producing a "whoop" sound.

At VUMC, the departments of pediatrics and preventive medicine have worked together with the help of community practitioners to test new pertussis vaccines, commonly known as DTP (diphtheria, tetanus and pertussis) vaccines. The culmination of these efforts was a large, multi-center study to evaluate 13 new vaccines. VUMC was chosen as the coordinating center.

"In the past decade, we've been very involved in evaluating new pertussis vaccines because there has been a great deal of concern about the old vaccine being associated with reactions and fever," said Dr. Kathryn M. Edwards, professor of Pediatrics.

"The centers participating in this research are chosen for their ability to recruit large numbers of children. We're among a handful of centers who are able to do studies like this based on superb community participation," Edwards said.

The DTP vaccine is typically given at two, four and six months of age. Boosters are given at 12 to 18 months and four to six years.

"There has been a large amount of patient dissatisfaction about the DTP vaccines," Edwards said. The Vanderbilt vaccine studies have gone on to be more thoroughly tested in countries in Europe, where there is no routine vaccination for pertussis.

As a culmination of that work, there are now three new pertussis vaccines that are licensed and given to young children. An advisory body of the Centers for Disease Control has recommended that the new vaccines replace the old one in routine use.

"We were chosen to be the coordinating center for one of these studies, a testimony to the fact that we have excellent statisticians in preventive medicine to coordinate the vaccine effort and good patient populations and to the organizational structure of our clinical research enterprise of the past two decades or more."

In the early 1980s, there was an increase in the number of children who were not immunized for pertussis because of worries about the side effects, which included high fever and, occasionally, seizures.

If a child acquires pertussis in the first six months of life, there are severe difficulties since the child's airways are much narrower than an adult's, Edwards said. Children with pertussis are also much more susceptible to bacterial infections.

"So the disease can cause death even in this time of very sophisticated, modern medicine," she said.

As a result of the fear of the old vaccine, there have been more reported cases of pertussis. In 1993, there were the highest number of pertussis cases in the United States since the vaccine was first used.

That year, there was a large outbreak of the disease in Chicago and Cincinnati. In Cincinnati, most of those who came down with pertussis had been immunized, but with the old vaccine.

"The old one is still out there, but it is recommended that it be replaced by the newer vaccine," Edwards said. "We anticipate the older vaccine be completely replaced over the next year or two," Edwards said.

The pertussis vaccine research would have been nearly impossible without the tremendous cooperation from the community, Edwards said.

"Vaccine testing is an effort spearheaded by Vanderbilt that has involved the Nashville community, practitioner's offices and several hundred children in Nashville who were immunized with these new vaccines," Edwards said.

"It's been a testimony to the fact that the community, parents and people at Vanderbilt have been able to work together to answer important questions and to replace the old vaccine with a safer, more effective vaccine.

As a corollary to the pertussis vaccine work, Vanderbilt has also studied pertussis in adults. Much of this work has been done by Dr. Seth W. Wright, associate professor of Emergency Medicine at VUMC.

Studies in the Vanderbilt Emergency Department have shown that around 21 percent of adults who come to the emergency room with a cough that has persisted for more than two weeks have pertussis. In another study conducted in California, the incidence of pertussis was found to be about the same as peptic ulcer disease in adults, Edwards said.

"These adults were all immunized as children, which suggests to us that immunity wanes," she said. Even the new vaccines wane in effectiveness, showing that there may be the need for adults to have booster vaccinations, Edwards said.

Vanderbilt will soon be conducting a large trial to see whether pertussis vaccines given to adults can actually prevent pertussis. About 250 people will be enrolled in the study.

Adults with pertussis usually don't have a fever. A persistent cough is the major symptom.

Once the cough begins, it can't be treated, Edwards said. The cough won't respond to any treatment. "If you're exposed to someone with pertussis, you can be treated with antibiotics and people with pertussis may be treated with antibiotics to prevent them from spreading the disease to other people.

"Having pertussis can be quite distressing," Edwards said. "These people may be out of work and incur a lot of medical care costs."