WASHINGTON, June 3 (UPI) -- A new combination vaccine awaiting approval by the Food and Drug Administration appears to boost the immunity to whooping cough in teens and adults, who can spread the disease to infants, where it can be life-threatening.
The findings come at a time when whooping cough, also known as pertussis, is on the rise in the United States. In 2004, there were nearly 19,000 cases, up from 11,700 in 2003.
"The arrival of a new combination vaccine for diphtheria, tetanus and pertussis represents a major advance," Dr. Michael Pichichero, the study's lead investigator and professor at the University of Rochester Medical Center, said in a statement. "Now with the availability of acellular pertussis vaccines for adolescents and adults, we can complete the cycle of immunization with booster shots to finally eliminate whooping cough in the United States."
The study, slated for publication in the June 22-29 issue of the Journal of the American Medical Association, was released online early because of its public health importance, the journal said in a statement.
The vaccine, known by its trade name Adacel, is manufactured by Sanofi Pasteur, based in Swiftwater, Pa. Approximately 6 million doses of Adacel have been administered in Canada and Europe, where it is already approved and appears to be safe and work "very well," Dr. David R. Johnson, director for scientific and medical affairs at Sanofi, told United Press International.
Sanofi funded the study and has awarded grants to two of the study authors. Two other study investigators also have ties to the pharmaceutical company.
Johnson said the arrangements did not influence the outcome of the study and noted some of the study authors had received support from Sanofi's competitors. "I certainly don't have any concern as a pediatrician and a parent that the relationship between the investigators and the sponsor is anything but fair and above board," he said.
Whooping cough, which gets its name from the whoop sound infected children sometimes make when gasping for breath during prolonged coughing episodes, was once a scourge, infecting more than 200,000 in 1934 and killing 8,000.
Vaccines against the disease have kept it in check -- there were only 13 deaths in 2003 -- but the increase of cases in adults and adolescents has generated concern among public-health officials. Last year, for the first time in the United States, there were more cases of whooping cough in teens and adults than in infants.
The concern is not only about the complications the disease can cause in adults, but also that they might transmit it to infants too young to have been immunized fully against the disease.
"Pertussis is a very unpleasant disease and also adults and adolescents can spread it to vulnerable infants who can sometimes die from it," Dr. Trudy Murphy, a medical epidemiologist with the Centers for Disease Control and Prevention in Atlanta, told UPI.
Murphy said adults also can suffer severe consequences from the disease, including developing pneumonia and coughing so hard they break a rib.
One problem in curtailing the disease has been a lack of booster vaccine for adults and teens. Although the whooping cough vaccine can provide protection during childhood, "the protective effects wane over time, so adolescents and adults become susceptible to pertussis again," Murphy said.
Unfortunate, but the childhood vaccine has proven too dangerous to be used as a booster in older individuals, because it can trigger severe reactions at the site of injection and swelling.
The new vaccine is based on what is thought to be safer technology. Instead of using entire bacterial cells -- a technique known as whole cell -- the vaccine incorporates only a few proteins found on the surface of the bacteria, also called acellular technique. This appears to provide enough cues for the immune system to be able to recognize the real whooping cough bacteria and shut it down.
In the study, nearly 4,500 adolescents and adults, ages 11 to 64, were tested at 39 clinical centers around the United States. They received either Adacel or the currently licensed vaccine for tetanus and diphtheria. Adacel elicited protective immune responses to pertussis, tetanus and diphtheria and appeared to be as safe as the licensed tetanus-diphtheria vaccine.
If the FDA approves Adacel, it would become the second available pertussis booster vaccine. GlaxoSmithKline's Boostrix was approved in May, but it is only indicated for adolescents ranging in age from 10 to 18 and not for adults.
Sanofi has asked the FDA to approve Adacel for individuals ranging from ages 11 to 64.
Murphy said it was likely the agency would approve Adacel, because the agency's vaccine advisory committee unanimously recommended the action last March. The FDA generally follows the advice of its advisory committees.
The CDC's Advisory Committee on Immunization Practices meets June 29 to determine whether the new vaccines should be used in mass-immunization booster-shot programs for tetanus and diphtheria.
"They are considering recommending the vaccines to replace tetanus and diphtheria booster vaccine for adolescents ... because the new vaccines also protect against pertussis," Murphy said. "It gives you more protection."
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Steve Mitchell is UPI's Medical Correspondent. E-mail: [email protected]
