Whooping Cough Update.

The FDA recently approved a new whooping cough vaccine that uses only a portion of the pertussis bacterium instead of the entire bacterium used in current immunizations. This "acellular" injection causes 50 to 90 percent fewer cases of fever, swelling, and other side effects. It's too early to know if the new vaccine causes fewer of the very rare side effects of seizures and brain damage because they are so rare they take tens of thousands of injections to detect, but Japan has been using the vaccine since 1993 apparently without incident.

The vaccine is still designed to be given to infants at two, four, and six months, with two booster doses to be given to older children between 15 months and age six.

Whooping Cough is a highly contagious disease that usually hits children under age three. But new research has shown that infections in adults are common and usually go unrecognized.

Twelve to 31 percent of adults with a persistent cough probably have pertussis. It is now estimated to be as widespread in the population as peptic ulcer disease. By the time an adult finally gets fed up enough to go to a doctor, the immune system may already have killed the pertussis bacterium. But one of several toxins exuded by the pertussis bacterium damages airway cells involved in the cough reflex, so the harsh cough continues. (It's frequently called the 100-day cough.)

If doctors can stop pertussis in adults and teem, they might be able to quench the outbreaks of pertussis that kill or disable infants. The development of this new crop of pertussis vaccines has spurred talk of a booster program for adults. In theory, adults would get booster shots of a pertussis vaccine every ten years or so, but scientists have to determine how long the immunity really lasts first.

There is evidence that many cases of Sudden Infant Death syndrome may be linked with pertussis infections. Researchers from the University of California and the University Hospital in Erlangen, Germany, studied 51 babies who had died of SIDS and found that 18 percent had evidence of pertussis infection. The pertussis bacterium attacks the airway cells in young infants, who may not be strong enough to cough. They simply exhale a lot of air without inhaling enough to replace it. Rather than the cough and whoop of an older child, a newborn with pertussis may simply appear to hold its breath periodically. Pertussis would not normally be implicated on autopsy because it is so difficult to culture.

-- Science News, 7/20/96