By Adam Marcus HealthDay Reporter

Updated on June 15, 2022

THURSDAY, July 18, 2002 (HealthDayNews) -- Whooping cough may no longer be the menace it once was, but here's a warning against complacency.

The once-feared pertussis bacteria that causes whooping cough claimed 17 lives in the United States in 2000, a year that saw the highest number of cases of the disease since 1967, according to a report released today by federal health officials. All the victims were infants who hadn't been fully immunized against the germ.

"We have noticed an increase in deaths and an increase in cases in infants less than four months of age, and that's likely indicating an increase in circulating bacteria," says Dr. Kris Bisgard, an epidemiologist at the U.S. Centers for Disease Control and Prevention, and a co-author of the study.

Starting at two months of age, children should receive three doses of the pertussis vaccine -- which are combined into shots, DtaP, that also prevent diphtheria and tetanus -- by the time they're six months old. But the inoculations haven't been proven safe in babies younger than two months, leaving a sizable window of jeopardy to infection.

Although the germs can be killed with antibiotics, in some cases the attack is so strong that by the time it's diagnosed, even drugs can't control the disease. The latest study reports on two such instances, involving infants who died of whooping cough two years ago.

The 17 deaths occurred in 12 states, and symptoms of the illness began before all the children were four months old. That year, 7,867 Americans were diagnosed with whooping cough, although Bisgard says the true incidence of the disease is probably higher. Before a vaccine was available, whooping cough struck 200,000 people a year in this country.

Preliminary figures for 2001 show a slight decline in pertussis cases, to 7,580, with 14 deaths. Bisgard says it's too soon to declare the infection flagging.

The DTaP vaccine is among the most widely administered inoculations, with better than 90 percent coverage in children, Bisgard says. Still, the incidence of pertussis jumped 50 percent between 1980 and 1998.

Since the vaccine isn't 100 percent effective against the bacteria, if more of the germs are around, more partially immune people will be exposed to them. Immunity to pertussis also wanes over time, and adolescents and adults are vulnerable to generally mild cases of the disease that are hard to distinguish from other respiratory ailments.

As a result, they rarely seek treatment for their cough, allowing themselves to serve as reservoirs of infection for babies.

"It's a very infectious disease, and by the time it's finally diagnosed, the delay in seeking health care lets the disease spread through a household," Bisgard says. Pertussis spreads through respiratory droplets expelled in coughs, and, to a lesser extent, in secretions left on shared drinking glasses.

Unless brought to heel, the bacteria ravage the lungs, depriving patients of oxygen. That lack of oxygen -- called anoxia -- can lead to fatal brain damage and heart attacks.

Bisgard says parents should keep young infants away from people with newly developed coughs. And pediatricians should consider whooping cough a potential threat to their youngest patients, she adds.

Dr. Carol J. Baker, a pediatrician at Baylor College of Medicine in Houston, says doctors also need to be on the lookout for pertussis in older children and adolescents.

"This is where we're beginning to see a lot more disease and a lot more concern," she says.

Baker says scientists are now investigating whether giving older children an additional inoculation against pertussis to restore their immunity might help quash the infection.

What To Do

To find out more about whooping cough, visit KidsHealth, or the Centers for Disease Control and Prevention. (To read the CDC overview, you'll need the Adobe Acrobat Reader, which you can download by clicking here.)

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