New Pertussis Vaccine Effective in Teens, Adults

All should be vaccinated, researchers say

THURSDAY, June 2, 2005 (HealthDayNews) -- A new vaccine is highly effective against pertussis -- also called whooping cough -- a disease that not only poses problems for infants but is increasingly common among U.S. teens and adults, researchers report.

This new combination vaccine, which is not yet available to the public, provides booster immunity against tetanus, diphtheria and pertussis for adolescents and adults. And it's as safe as the current tetanus-diphtheria vaccine, the researchers said.

"This study is of major public health importance," said lead researcher Dr. Michael E. Pichichero, a professor of microbiology and immunology at the University of Rochester Medical Center. "The study shows that a brand new special formula whooping cough vaccine for teenagers and adults is very safe and effective."

The report was published online Thursday by the Journal of the American Medical Association. It was released early because of its important public health implications. The print version of the study will appear in the June 22-29 issue of the journal.

In 2004 there was a dramatic increase in the number of pertussis cases in the United States. That year there were 18,957 reported cases, up from 11,647 cases reported in 2003. And for the first time, there were more cases of whooping cough reported among teens and adults than infants, according to the U.S. Centers for Disease Control and Prevention.

"This is only the tip of the iceberg," Pichichero said. "There are 1 million to 2 million cases in the U.S. every year in teenagers and adults. The diagnosis is largely missed by physicians. It is diagnosed as common bronchitis or prolonged allergy," he said.

Pertussis is a highly contagious, potentially fatal bacterial disease that affects the respiratory system. It produces coughing jags that may end in a high-pitched, deep inspiration -- the "whoop." Before widespread immunization, pertussis was most common in infants and young children. But now that most children are immunized before school age, a higher percentage of cases are seen among teens and adults, according to the National Library of Medicine.

For the new study, Pichichero's team tested the current tetanus-diphtheria vaccine against the new tetanus-diphtheria-pertussis vaccine. The vaccines were tested on 4,480 teens and adults from August 2001 to August 2002 at 39 centers in the United States.

Of those participating in the trial, 2,053 were adolescents: 1,213 received the new vaccine and 815 received the older vaccine. There were also 2,427 adults in the study: 1,804 received the new vaccine and 599 received the older one.

The researchers found that the new vaccine produced "a robust immune response in adolescents and adults to pertussis, tetanus and diphtheria antigens, while exhibiting an overall safety profile similar to that of a licensed vaccine."

The vaccine tested in this study is called Adacel, and is made by Aventis Pasteur, Pichichero said. While this vaccine has not yet been approved by the U.S. Food and Drug Administration, it is similar to another pertussis/diphtheria/tetanus vaccine called Boostrix, which was approved by the FDA in May for use in teenagers. Boostrix is made by GlaxoSmithKline, Pichichero said.

The difference between the two vaccines is that the one tested in the new trial is for both teens and adults, Pichichero noted.

Based on these results, Pichichero said U.S. health officials should endorse this vaccine this month, and recommend it for all American teenagers. The vaccine is also recommended for some adults, including women of childbearing age who could transmit whooping cough to young babies.

"This is a new vaccine, it's safe and effective," Pichichero said. "As soon as it's available at your doctor's office, don't walk, run to receive it."

"The government is going to recommend universal vaccination," Pichichero added. "Every teenager in America will be recommended to receive the vaccine. The hope is with widespread use we will be able to eliminate whooping cough from the United States, just as we've done with polio, measles and other vaccine-preventable diseases."

One expert agrees this new vaccine is a step forward.

"It answers a need that's been around for a while," said Dr. Jonathan Field, director of the allergy and immunology clinic at New York University Bellevue Medical Center, in New York City. "I knew there had been increases in the number of pertussis cases, but I was unaware it was a 60 percent increase," he added.

Field noted that if you're getting the regular recommend 10-year booster shots for tetanus and diphtheria, why not also get one for whooping cough.

Recommending the vaccine is a positive public health measure, Field said. "There is a lot of upside to preventing pertussis," he said. "The bright side is if you have a strong worldwide vaccine program you may be able to eradicate it."

More information

The National Library of Medicine can tell you more about whooping cough.

SOURCES: Michael E. Pichichero, M.D., professor of microbiology and immunology, University of Rochester Medical Center, Rochester, N.Y.; Jonathan Field, M.D., director, allergy and immunology clinic, New York University Bellevue Medical Center, New York City; June 2, 2005, early online release Journal of the American Medical Association
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