The baby was born healthy but developed a cough when he was eight days old. An older sibling in the family had been coughing too. Three weeks later, the baby was diagnosed with the infectious disease pertussis, hospitalized, and placed on a ventilator in an intensive care unit. But he died nine days later.
His mother had received a pertussis vaccine—called the Tdap—two years earlier, after she had given birth to another child, and the baby's siblings had been immunized too. When everyone in a family receives pertussis vaccine, newborns who are vulnerable to the illness are supposed to be protected.
But that's not what happened.
"They did everything right, but the mother's postpartum Tdap from two years ago was not enough," said Dr. Jennifer Liang, an epidemiologist with the Centers for Disease Control and Prevention.
Widespread pertussis outbreaks in the United States have raised concerns about the disease to their highest levels in decades. On Wednesday, public health officials attempted to try to thwart the impact of the disease by recommending that prenatal care providers immunize all pregnant women.
Pertussis, commonly known as whooping cough, is highly contagious. People who pick up the bacterial infection typically develop an uncontrollable cough that leaves them breathless and causes the telltale "whooping" sound as they gasp for air. The illness is treated with antibiotics, but can be deadly in infants and people with other health conditions.
The growing pertussis outbreak has baffled and frustrated public health officials. A vaccine for the disease has been available for more than 60 years and eventually reduced cases from around 200,000 per year in the 1940s to fewer than 1,000 in the 1980s.
But not this year. U.S. pertussis cases in 2012 are the highest since 1959, Dr. Sarah Meyer, of the CDC's Epidemic Intelligence Service, said Wednesday at a meeting of the CDC Advisory Committee on Immunizations Practices in Atlanta. So far, 32,645 cases have been reported. Thirty-two states report having at least twice as many pertussis cases this year compared to 2011. Most of the 16 deaths so far this year are in infants.
In light of the record number of cases, immunizing pregnant women to protect infants is imperative, Meyer said. Studies demonstrate that when a woman is vaccinated in the later part of pregnancy, antibodies are passed to the fetus that provide some protection against the disease early in life. The five-dose vaccine series called DTaP (protecting against diphtheria, tetanus and pertussis) that babies and young children routinely receive doesn't begin until two months of age and doesn't confer full immunity until the series is completed.
As pertussis cases rise, public health officials have been searching for a strategy to protect infants. Prior to 2011, the CDC recommended that pregnant women receive the vaccine following childbirth and that family members and others in close contact with the infant receive a booster shot as well. That strategy failed because of difficulties in providing the vaccine to so many people in the infant's inner circle, Liang said.
Last year, the CDC switched strategies, recommending vaccination in the later third of pregnancy for women who had not previously received a Tdap. However, studies show a poor response to that guideline, with only 2.6 percent pregnant women getting immunized, Liang said.
The new recommendation—reached on a vote of 14 to 0 by the CDC's advisory committee—builds on those earlier attempts by simplifying the message to prenatal care providers and pregnant women. The committee now advises that all pregnant women receive a Tdap—regardless of whether the woman has received a pertussis vaccine in the past—and that the shot be given during pregnancy, although the optimal time period for getting the shot is from 27 to 36 weeks gestation .
If not administered during pregnancy, Tdap should be administered immediately postpartum, the committee said.
"Vaccination during pregnancy could avert more cases and deaths at no additional cost," Liang said. "A more universal recommendation for pregnant women would remove real or perceived barriers to vaccination."
The onus is now on healthcare providers to add a pertussis vaccine to routine prenatal care and for pregnant women to make sure they get the shot. But that still won't solve the pertussis outbreak, health experts note. An additional concern for federal health officials is that too few adolescents and adults are getting their Tdap shots. The CDC recommends a single booster dose of the vaccine for teens ages 11 to 18 age (preferably at age 11-12 years) and once again for adults 19 through 64.
While 95 percent of U.S. children receive the initial five-dose series, Americans are not adhering as well to the booster shot guidelines, according to Dr. Mark Sawyer, chair of the working group on pertussis vaccine and a pediatric infectious diseases specialist at the University of California, San Diego. Only 78 percent of teens and 8 percent of adults have received a booster shot.
"We have a long way to go in getting our adult population immunized," Sawyer said at Wednesday's meeting.
Still another problem is with the vaccine itself. The manufacturing of the pertussis vaccine was changed from a whole-cell formulation to an acellular vaccine in the 1990s in order to reduce side effects. But the current outbreaks suggests that the acellular vaccine isn't as strong. Many of the U.S. outbreaks are in children ages 7 to 10 who received the newer acellular vaccine series or in teens ages 13 to 14 who received the acellular booster shot.
Pharmaceutical companies are exploring a better vaccine, said Leonard Friedland, senior director at GlaxoSmithKline. But, he added: "While there have been outbreaks,vaccination is still the most important strategy to control pertussis outbreaks in the United States."
Question: Do you support the federal government's recommendations for pertussis vaccination? Tell us your thoughts in the comments.
Shari Roan is an award-winning health writer based in Southern California. She is the author of three books on health and science subjects.
- Public Health
- pertussis vaccine