When Avery Holdsworth was 3 months old, she began coughing so hard that "she would almost lift her little body off the crib mattress," remembers her mother, Amanda Holdsworth, of Howell, Michigan.
When she wasn't coughing, which was most of the time, Avery looked fine. And she didn't have a runny nose or a fever. However, the cough was so severe that Holdsworth took her daughter to the pediatrician three times in ten days. The doctor ruled out RSV (respiratory syncytial virus) and allergies, but the cough continued. Finally, Holdsworth's husband suggested having Avery tested for pertussis because a client's child had recently been diagnosed with it.
"I said, 'Whooping cough? Isn't that like a Little House on the Prairie disease?'" recalls Holdsworth. She was shocked when Avery tested positive.
Once upon a time, whooping cough (or pertussis) was as dreaded a disease as polio, says Parents advisor Harley Rotbart, M.D., professor of pediatric infectious diseases at the University of Colorado School of Medicine and Children's Hospital of Colorado in Aurora. "It was a quite severe, life-threatening bacterial illness that took young babies from parents."
But we've grown up in the era of pertussis vaccination. The DTaP vaccine (which combines diphtheria, tetanus, and pertussis) is given to children at 2 months, 4 months, and 6 months, and again between 15 and 18 months and 4 to 6 years of age. Most parents have never seen or heard whooping cough because widespread immunization campaigns dramatically reduced the rate of the disease. After the vaccine was introduced in the 1940s, cases declined by more than 99 percent. By 1976, there were only about 1,000 cases nationwide.
Unfortunately, it's a drastically different situation today. Pertussis is on the upswing, thanks to what some experts call a perfect storm of innocent ignorance, anti-vaccine sentiment, and less-than-perfect immunizations. In 2012, more than 41,000 confirmed cases of whooping cough were reported to the Centers for Disease Control and Prevention (CDC) -- the most since 1955. "That's likely just the tip of the iceberg," says Mary Anne Jackson, M.D., section chief of infectious disease at Children's Mercy Hospital, in Kansas City, Missouri. "Many cases go undiagnosed and many don't get treated with antibiotics, so the disease continues to spread." Babies are at highest risk of getting pertussis and becoming dangerously ill, but more school-age children are getting sick than ever before too.
One of the biggest dangers of the disease is that it is often not diagnosed until it has progressed to a more serious stage, when breathing becomes difficult. At that point it's easy to develop respiratory infections like pneumonia. "Children can literally suffocate because they cannot catch their breath. Their cough and whoop can be so severe that they die of oxygen deprivation," Dr. Rotbart explains. Understanding the facts about the disease known as "the 100-day cough" will go a long way to helping prevent it.
The earliest pertussis vaccines, called "whole-cell," were made from the entire pertussis bacterium and were nearly 95 percent effective. However, the public worried that they may have sometimes caused serious nervous-system side effects, such as seizures. Though studies never proved that, scientists created a safer "acellular" vaccine that uses only part of the bacterium. This is the shot American kids have gotten since 1990.
But after a startling number of vaccinated preteens in California came down with whooping cough in 2004, researchers investigated and learned that the current vaccine can be as low as 70 percent effective, Dr. Jackson says. Doctors also suspect that the immunity the vaccine does confer may wear off over time. A study published last year found exactly that: Immunity wanes after the fifth dose, traditionally given before kids enter kindergarten, which explains why so many kids ages 7 to 10 are coming down with pertussis. In fact, children who have not received all five of the recommended DTaP shots are eight times more likely to get whooping cough than those who are fully immunized, reports the CDC. Since 2005, it's been recommended that kids receive a booster shot called Tdap (tetanus, diphtheria, and pertussis) at age 11 or 12. Kids 7 to 10 who haven't gotten all five doses of DTap should also receive a single dose of Tdap. Some experts believe every 7- to 10-year-old should get Tdap, but that hasn't been officially recommended yet.
Only about 70 to 85 percent of teens and roughly 13 percent of all adults are fully immunized against pertussis, says the CDC. If vaccinated kids do get sick, they may still cough for an extended time but generally won't be as ill as kids who haven't gotten the booster.