CDC Calls for Pertussis Vigilance

By Mike Bassett

As the incidence of pertussis increases across the country, the CDC recommends that adults, including those aged 65 and older, receive a vaccination against whooping cough.

With the increasing incidence of pertussis plus evidence that the effectiveness of vaccinations against the disease wanes over time, it has become clear that this condition, also known as whooping cough, can no longer be considered just a childhood disease.

According to the Centers for Disease Control and Prevention, as of November 21, 2012, forty-nine states and Washington, DC, have reported increases in the number of pertussis cases compared with the same time period in 2011. More than 38,000 cases of pertussis, including 16 pertussis-related deaths, have been reported to the CDC this year.

While most pertussis-related deaths occur among infants under the age of 3 months, and the incidence rates are highest for infants and children up to the age of 14, the CDC is now recommending that all adults—even those over the age of 65—be vaccinated for the disease.

Mary Elizabeth Roth, MD, who recently accepted a position as vice dean for graduate medical education at the Charles E. Schmidt College of Medicine at Florida Atlantic University, got a pertussis booster shot when she reached the age of 64. “I’m immune suppressed, been on steroids, and have asthma, so I don’t want anything with a prolonged cough,” she says. “My mother had whooping cough so, in my mind, it’s something you don’t want to get.”

A 50-year-old pediatrician in Roth’s community is a poster child for why pertussis should no longer be considered a disease of the young, Roth says. This pediatrician had symptoms associated with pertussis for six weeks before being diagnosed with the disease. Accordingly, he was contagious and posed a risk to his patients for five days before exhibiting the first symptoms up through five days after he started receiving treatment.

The disease has a particularly telling symptom, according to Rosemary Laird, MD, medical director of the Health First Aging Institute and The Center for Family Caregivers in Melbourne, Florida: a persistent, severe cough that often comes with the whooping sound associated with pertussis. The cough can be worse at night, which can also help with the diagnosis.

The problem, of course, is that over the years, the disease has rarely been diagnosed in adults. “Unless there is an epidemic in the community, no one is going to think about it [the possibility of pertussis] for several weeks,” Roth says. “But there is something different about this cough. It’s not the usual asthma or bronchitis, and that can help the physicians to start thinking about pertussis.”

“I’ve talked to several primary care providers in my area, and they haven’t seen too much in the way of pertussis among their seniors,” Laird says. “But the interesting thing is that they weren’t aware of the recent increase [in pertussis cases] and the issue of adults needing to get boosters.” Consequently, she says, it’s important that physicians become better informed about the rising incidence of pertussis and the CDC recommendations to vaccinate all adults, including the elderly.

Possible Complications
What are the potential complications associated with pertussis? First of all, the wracking cough can be debilitating. “It used to be talked about as the cough that could break ribs,” Laird says.

“You can get pneumonia with it,” Roth explains. “It is an inflammatory and infectious condition, so you can go on to have a fever, and anyone with a weakened heart and weakened lungs won’t have the capacity to cope with the inflammation. And the elderly who may have a little heart failure or a little pulmonary fibrosis or primary pulmonary disease won’t have the reserves to withstand coughing all the time.”

While aging adults should certainly be concerned about the impact pertussis can have on their well-being, there is another driving force behind the CDC’s decision to urge that all adults be vaccinated: the possibility that they could unwittingly infect infants who haven’t been vaccinated and have no immunity to the disease.

“All geriatricians and anyone caring for adults need to pay attention to this [pertussis] outbreak,” Laird says, adding that it will be helpful to educate primary care physicians about the waning immunity of pertussis vaccinations and the recommendations that aging adults who are in contact with newborns—or even with young children in general—should get immunized.

For those older adults and their physicians who are worried about potential side effects of the Tdap (tetanus-diphtheria-acellular pertussis) vaccine, a recent study by researchers at Kaiser Permanente Southern California published online in Clinical Infectious Diseases, should put them at ease. According to Hung Fu Tseng, PhD, a senior research scientist in the department of research and evaluation at the Southern California Permanente Medical Group, the elderly population was not included in the Tdap prelicensure clinical trial, “so the safety data regarding the vaccine used in that population is limited.”

But Tseng and his team found that elderly people receiving the Tdap vaccine were no more likely to suffer adverse reactions than others who’ve received the tetanus and diphtheria (Td) vaccine. According to Tseng, in the time immediately after the Tdap vaccination, there is a risk of some reaction in the area of the vaccination site, “But this is expected because we know that has happened with people who received Td. There’s some swelling and pain but nothing serious,” he says.

There also shouldn’t be any risk for individuals with compromised immune systems, Laird says. “Some of the concern about immunizing a person with a compromised immune system comes when the vaccine product is live and has infectious potential. This particular vaccine is not that kind, but I would recommend that everyone should talk to their healthcare providers [before getting the vaccine].”

Going forward, a major issue will be getting physicians to update their immunization protocols, Laird says. “We’re use to having protocols telling us to give boosters to adolescents when they are 11 or 12, but there haven’t been any recommendations up until now telling us adults need boosters,” she says. “That’s one of the reasons why we need to focus on educating primary care physicians so they can update their protocols.”

— Mike Bassett is a freelance writer based in Holliston, Massachusetts.