Herald staff and news services
WASHINGTON — Whooping cough is one of those diseases most people think is history, but the dangerous germ that can leave sufferers gasping for air is making a comeback.
The cough so strong it can break a rib once hit mostly babies and toddlers, but now it’s striking more and more teen-agers and young adults. Apparently the whooping cough vaccinations Americans get as babies eventually can wear off.
Here’s the real risk: While older people usually recover, they can easily spread the illness to infants too young for vaccinations. Whooping cough can kill babies.
So experts warn new parents to keep infants away from anyone who’s coughing, even as scientists study whether millions of Americans should start getting booster doses of whooping cough vaccine just as many get regular tetanus shots.
The goal is to develop boosters for older children and adults so there’s "a wall of protection around the newborn baby," explains Dr. Michael Decker, a Vanderbilt University professor who has studied whooping cough, also called pertussis, for 20 years. Decker just joined vaccine manufacturer Aventis Pasteur, which is working to bring a booster shot sold in Canada to this country.
Consider Decker’s own experience with the illness. "I got it off my 15-year-old this January, and I was coughing for three months," he said. "I could feel my throat closing up and tightening, and I started choking and gagging. It was a revelatory experience for someone who’s written the words and not experienced the feeling."
Often, though, older patients have a milder illness, just a nagging cough. So they don’t see a doctor, or it’s misdiagnosed as bronchitis, because pertussis testing is very difficult. Indeed, a Vanderbilt study found about one-fourth of teens and adults with prolonged coughs unknowingly have pertussis. It’s most contagious during the first three weeks.
The Centers for Disease Control and Prevention counted 56,775 whooping cough cases during the 1990s, a 51 percent increase from the 1980s — and a rise that’s continuing.
In Snohomish County, however, there has been little sign of an increase in the disease, said Dr. Ward Hinds, health officer at the Snohomish Health District. Six cases of the illness were reported in the first seven months of the year, marking a steady decline from earlier years. In 1998, 38 cases were reported in the first seven months, followed by 33 in 1999 and 25 in 2000.
Hinds was unsure about why the drop occurred. He said the number of infections can fluctuate widely from year to year.
"I can say we’re not seeing an increase. That much is clear," he said.
Last year, CDC had reports of more than 7,000 cases, and "we suspect there may be 10 times that amount" because of underdiagnosis in teens and young adults, Dr. Kris Bisgard, a CDC epidemiologist, said.
That’s still a far cry from the 250,000 Americans who once got pertussis annually before vaccinations began in the 1940s. But it’s far worse than 1980, when there were only about 1,000 cases a year.
The biggest rise: CDC figures show for every 1 million 10- to 19-year-olds, three got pertussis in 1980 vs. 70 cases per million older children last year.
They in turn can infect vulnerable infants. Pertussis rose 37 percent among babies in the 1990s, almost exclusively among those younger than 4 months. That’s when infants get their second dose of pertussis vaccine, and protection begins kicking in.
Today, Americans get their final dose of pertussis vaccine by age 6.
Studies show that giving one-third of the youngster’s dose to teens and adults boosts their immunity nicely, CDC’s Bisgard said. Canadians already can get just such a booster dose.
Americans can get booster doses of tetanus and diphtheria vaccine every 10 years. (It’s called a tetanus shot, but the two almost always come together.) The idea: Just add a pertussis booster to that shot. After all, babies today get diphtheria, tetanus and pertussis vaccine in the same shot, called DTaP.
For now, what’s the advice?
Keep infants away from people who have any cough illness, Bisgard said — and make sure they’re vaccinated on time. DTaP doses are given at ages 2, 4 and 6 months, again at 15 to 18 months and a final dose between 4 and 6 years.