May 15, 2012 in Features

Pertussis shows persistence

Common in the 1940s, cases of whooping cough show rise in the Northwest
By The Spokesman-Review
 

The whooping cough epidemic plaguing other counties in Washington has been slow to reach the Inland Northwest.

While numbers in West Side counties continued to climb at the end of last week, Spokane County had 18 confirmed cases. (Skagit County, the state’s hardest hit, had close to 300.) In North Idaho, Kootenai and Bonner counties each had two cases.

But Spokane County already has more cases than it saw in all of 2011. And health officials say the actual number of infected people is far higher than the number of tested and confirmed cases.

One certainty when it comes to whooping cough: It poses the biggest threat to new babies, who comprise the vast majority of whooping case deaths. Efforts to control the disease’s spread largely amount to an effort to protect babies from serious injuries or death.

An uncertainty: What happens next. The number of cases in the Inland Northwest could level off, officials say, or they could blow up.

“You never can predict what’s going to happen with infectious diseases,” said Dr. Joel McCullough, health officer for the Spokane Regional Health District.

Here are some questions and answers about whooping cough, its symptoms and the vaccine that helps to stem it.

Q. What are the symptoms?

A. Whooping cough, also known as pertussis, has three stages, said Dr. Anna Barber, a pediatrician at Providence Pediatrics North.

Stage 1 seems like a cold and lasts a week or two. You might be sneezing and congested, with a mild fever and dry cough.

Stage 2, marked by fits of coughing that might lead to vomiting, lasts from one to six weeks. For babies, the fits often end with a high-pitched “whooping” sound as they sharply draw in breath. Not everyone whoops, though – older children and adults might suffer only a hacking cough. Very young infants with pertussis might never cough.

Babies might stop breathing or turn blue because they’re deprived of oxygen. Infected infants also may eat poorly or have coldlike symptoms – congestion, sneezing – that last longer than you’d expect.

Stage 3 is a cough that can linger for months.

“A lot of people call this the 100-day cough,” Barber said.

Q. How is it spread?

A. Whooping cough, caused by highly contagious bacteria, is spread through the tiny droplets that enter the air when an infected person coughs, sneezes or speaks. Other ways to spread it: sharing utensils, kissing, sharing water bottles.

Infants often get it from adults who don’t realize they’re infected. That’s why health care providers urge adults who will have contact with infants – including pregnant women – to get immunized.

If he were infected as an adult, suffering only mild symptoms, “I could pass along pertussis to a baby, and it could actually be deadly to them,” said Roy Almeida, director of epidemiology at Providence Sacred Heart Medical Center.

Q. Who’s at highest risk?

A. For adolescents and adults, whooping cough often amounts to a cough that drags on. While it can be exhausting, it’s usually mostly irritating. For babies, however, whooping cough can be fatal.

Infants 3 months and younger accounted for 83 percent of the whooping cough deaths reported to the Centers for Disease Control and Prevention from 2004 to 2008.

Some babies cough so much they’re unable to catch their breath. But because other infected infants never cough, their parents don’t suspect pertussis until their babies turn blue, Barber said.

“They just stop breathing, and if they don’t get help they can die,” she said.

Also at high risk: pregnant women and health care workers, said Bill Edstrom, an epidemiologist with the Spokane Regional Health District.

Women should get vaccinated after 20 weeks into their pregnancies but two weeks before giving birth, he said. And health care workers who overestimate the power of the vaccine – it’s not foolproof – and go without masks or other preventive measures put themselves and others at risk, he said.

Q. Why are infants so vulnerable?

A. Infants can’t start the five-shot vaccination until they’re 2 months old, and even then they’re not fully vaccinated; the fifth shot comes when the child is 4 to 6 years old.

And the bacteria can easily overwhelm infants’ immature immune systems, said David Hylsky, an epidemiologist with the Panhandle Health District in North Idaho.

“The bacteria produces this toxin that helps it establish itself in the respiratory tract,” he said. “Really young kids that are still developing have a really tough time dealing with the toxin.”

Their bodies can’t expel mucus from their lungs, leading to secondary infections such as pneumonia and ear infections. Some develop brain swelling.

Q. How is pertussis treated?

A. Patients are prescribed a five-day antibiotic, Barber said – but not to treat the illness. By the time patients are past their “common cold” symptoms and arrive at a doctor’s office and a diagnosis, it’s too late for that.

Instead, Barber said, the antibiotic makes you not contagious. “We’re treating so they don’t spread it,” she said.

As the illness worsens, some people are hospitalized so they can be monitored. They also might receive oxygen or be placed on a ventilator.

Q. Should people with whooping cough be isolated?

A. Infected patients who end up hospitalized are put on “droplet precautions,” said Almeida, of Sacred Heart – they’re put in a room by themselves, and anyone who goes near them must wear a mask.

Patients at home should stay there – away from work, school or day care, said Hylsky, the North Idaho epidemiologist.

“Stay away from anybody until you’ve been on antibiotics for five days,” or until about three weeks after your symptoms began. Until then, you’re contagious.

Q. Are schools and day cares required to report when a student has pertussis?

A. Yes. In Washington and Idaho, schools and day cares must inform their local public health authorities when they have a confirmed case of whooping cough.

Regional health districts then work with the school or day care to tell other parents their children might have been exposed.

Q. What should you do if your child has been exposed?

A. The chance your child will catch whooping cough depends on their contact with the sick child and whether they’ve been vaccinated.

If your child shares a classroom, or a desk, with an infected child, they’re at greater risk.

“They should probably at least contact their family physician and see if they need to be tested or treated,” Barber said.

In particular, Edstrom said, make sure your kids’ vaccines are up to date and watch out for coughs that last longer than two weeks.

Q. How does the vaccine work for kids?

A. While there are several vaccine formulations used to prevent pertussis, DTaP is given to kids younger than 7, according to the CDC. DTaP also prevents diphtheria and tetanus.

Babies should get their first DTaP shot at 2 months old, health officials say. More doses are given at 4 months, 6 months, 15 to 18 months, and 4 to 6 years.

Q. If you were vaccinated as a child, do you need another shot as an adult?

A. Yes, health officials say.

It takes one booster shot of Tdap – a different formulation from DTaP – to protect adolescents and adults, according to the CDC.

In past years, patients who went into emergency rooms with nail-puncture or other injuries were given the Td vaccine, which protects against tetanus (or “lockjaw”) and diphtheria. The Tdap vaccine – which added a pertussis vaccine into the mix – was licensed in 2005 for adolescents and adults.

There’s been a push to give adults and older children that more-comprehensive booster when they arrive in ERs and urgent care centers, Hylsky said.

While the CDC is saying for now that one booster is all you need for life, there’s been no final verdict, said Edstrom, the Spokane epidemiologist.

Tdap hasn’t been out long enough for officials to know for sure whether, and when, the booster’s effectiveness will wane.

Q. Why has whooping cough resurfaced?

A. Health officials point first to lower immunization rates as a reason for the illness’s widespread return.

Before the vaccine became available in the 1940s, pertussis was one of the most common childhood diseases, according to the CDC. More than 200,000 cases were reported a year in the U.S.

After the vaccine came into widespread use, those numbers dropped. In 2010, 27,550 cases whooping cough were reported in the U.S.

But its return has coincided with declining vaccination rates as more parents receive vaccine exemptions for their children.

Other factors may be at play, too, Edstrom said:

• As the statewide epidemic grows, more doctors and patients have pertussis on their minds. Patients are more likely to seek attention for a cough they’d otherwise wait out. Doctors are more likely to test for pertussis.

• The vaccine isn’t foolproof, and its effectiveness can wane.

• Pertussis is a naturally cyclical illness. The number of cases naturally peaks every few years.


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