Pertussis Is Latest Disease Outbreak Concern in United States

FP Offers Advice on Reinforcing Need for Immunization

June 25, 2014 01:35 pm Chris Crawford

2014 brought a pertussis outbreak to California that has exploded in recent weeks. As of June 10, the California Department of Public Health (CDPH) had received reports of 3,458 cases of pertussis, with more than 800 cases occurring in the past three weeks, according to a news release(

[Doctor with stethoscope listening to coughing child in exam room]

Declared an epidemic by CDPH Director Ron Chapman, M.D., M.P.H., the latest pertussis figure marks a considerable increase from the 2,530 cases reported to the CDPH in all of 2013, according to the agency's June 10 pertussis report(

The number of pertussis cases nationwide this year also is cause for concern. Through June 16, 9,964 cases of pertussis have been reported to the CDC by 50 states and Washington, D.C. According to the agency(, this figure represents a 24 percent increase compared with the same period in 2013.

Breaking Down California's Pertussis Epidemic

In California, more than 80 percent of this year's pertussis cases have occurred in infants and in children ages 7-16 years. Of the infected patients requiring hospitalization, infants younger than age 4 months made up 65 percent of the cases. Two infant deaths have been reported.

"Preventing severe disease and death in infants is our highest priority," said Chapman in the news release. "We urge all pregnant women to get vaccinated. We also urge parents to vaccinate infants as soon as possible."

Story highlights
  • As of June 10, 3,458 cases of pertussis had been reported to the California Department of Public Health for 2014, with more than 800 cases occurring in the past three weeks.
  • Through June 16 of this year, 9,964 cases of pertussis have been reported to the CDC by 50 states and Washington, D.C., representing a 24 percent increase compared with the same period in 2013.
  • As has previously been the case with measles and mumps, educating reluctant parents about the benefits and potential risks of vaccinating their children against pertussis seems to be the best method to help control disease outbreaks.

Tetanus, diphtheria and acellular pertussis (Tdap) vaccination among pregnant women is the best way to protect infants who are too young to be vaccinated, said the CDPH news release. All pregnant women should be vaccinated with Tdap in the third trimester of each pregnancy, regardless of previous Tdap vaccination. In addition, infants should be vaccinated with diphtheria and tetanus toxoids and acellular pertussis adsorbed (DTaP) vaccine as soon as possible, the CDPH suggested. The first dose of DTaP vaccine can be given as early as 6 weeks of age.

"Unlike some other vaccine-preventable diseases, like measles, neither vaccination nor illness from pertussis offers lifetime immunity," Chapman said. "However, vaccination is still the best defense against this potentially fatal disease."

California doesn't have to look back very far for guidance on managing a pertussis epidemic. In 2010, 9,159 cases were reported in the state. A Pediatrics study( published last September examined the connection between nonmedical vaccine exemptions and pertussis in California during the 2010 outbreak. The researchers concluded that large clusters of intentionally unvaccinated or undervaccinated people can lead to pertussis outbreaks.

Worth noting is the fact that the CDPH's pertussis report suggested a possible link between the current outbreak and the use of acellular pertussis vaccines, "which cause fewer reactions than whole-cell vaccines that preceded them, but do not protect as long."

Another Pediatrics study( published in June 2009 examined pertussis cases in Colorado and found that pertussis vaccine refusers had a 23-fold increased risk for pertussis when compared with vaccine acceptors.

Discussing Pertussis Vaccination With Patients

As has been the case with measles and mumps, educating reluctant parents( about the benefits and potential risks of vaccinating their children against pertussis is an excellent way to help control disease outbreaks.

AAFP member Beth Loney Oller, M.D., of Stockton, Kan., said she begins a discussion about pertussis vaccination by explaining that the disease is spread through respiratory droplets, so coughing and sneezing are the usual methods of transmission. "You can be in a waiting room, grocery store or family member's house and be exposed to pertussis, or touch something with droplets from someone sneezing or coughing and contract the disease," she said. "Many infants are infected by older siblings, parents or caregivers who do not even know they are infected."

Loney Oller said she also talks with parents about the 2010 pertussis outbreak in California, in which 10 infants died from the disease. "All of these infants were under 3 months old and thus not fully protected by vaccination, which allows me to speak of the importance of 'cocooning' the child -- getting everyone around the child vaccinated (e.g., parents, older siblings, grandparents, daycare providers)," she said.

At the hospital where she practices, Loney Oller said they have what's called the "Cocoon Project," which offers -- at no charge -- five booster vaccines to anyone a pregnant or new mother chooses. "I also give all of my pregnant mothers the vaccine between 27-36 weeks per recent guidelines, because this helps with the infant's immunity," she added.

When it comes to reassuring hesitant parents about the safety of the pertussis vaccine for their children, Loney Oller said she uses resources jointly developed by the CDC, the AAFP and the American Academy of Pediatrics(

"The information I highlight is that serious reactions to the DTaP vaccine occur in fewer than one in a million children, but in 2000-2012, there were 225 deaths from whooping cough in the U.S., and almost all deaths (221 of 225) were in babies younger than 3 months," she said. "Approximately half of infants less than 1 year of age who get pertussis are hospitalized( -- a very scary statistic. So a very low risk with vaccine, while a much higher risk of bad outcomes if a child gets the disease."

Loney Oller said she has guided some parents to the CDC website to read stories told by families affected by vaccine-preventable illness, including pertussis( She also refers people to, a website hosted by the California Immunization Coalition that shares stories of vaccine-preventable illness. "It is very hard to not be touched by these stories," she said.