Why Is Whooping Cough Seemingly Back With a Vengeance?

Only 70 or so years ago, whooping cough was a dreaded disease in the United States that each year sickened 200,000 kids and killed as many as 9,000 of them. After the development and introduction of the pertussis vaccine in the 1940s, the number of reported cases plummeted. Today, between 10,000 and 40,000 annual cases are reported, causing from 10 to 20 deaths.¹

In 2014, however, the number of reported cases of whooping cough have risen dramatically in parts of the United States (see CDC map), outpacing the overall increasing trend that has been observed since the 1980s.¹ The CDC reported a 24% increase in nationwide pertussis cases in the first 6 months of 2014 compared with the first 6 months of 2014. 

Some state health departments have reported 45% or more increases in the 2014 rate over the 2013 rate. Ohio, Florida, Michigan, Nevada, and Idaho have all reported higher than usual incidence of the disease. California — particularly Southern California and San Diego County — has been especially hard-hit, with a record-breaking number of cases already reported as of August 4. 

While many are quick to point a finger at parents who do not or will not have their children vaccinated against infection with Bordetella pertussis — and that's certainly part of the problem — the reasons for the increasing prevalence of this preventable disease are more complex than that. The CDC notes that while children who have not received DTaP vaccines are 8 times more likely to get pertussis than vaccinated children, "they are not the driving force behind the large scale outbreaks or epidemics."¹

As is widely known, the original whole-cell pertussis vaccine had been associated with higher rates of minor, temporary adverse effects (such as fever and injection site swelling and pain) and, rarely, serious neurologic adverse reactions. Concern about these effects led to the development of today's acellular pertussis vaccines. While acellular pertussis vaccines are 80% to 90% effective in children who get all 5 doses on schedule, the vaccine's effectiveness wanes slightly each year after the 5th year.²

So while it's important to urge parents to have their children vaccinated (or even mandate it if they want your care to continue), it's also important to explain the importance of adhering to the long-term vaccination schedule for children, and to recommend that adults or adolescents (including pregnant women) who will be around infants get the recommended pertussis booster vaccine dose on time.³

—Michael Gerchufsky

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References

1. Centers for Disease Control and Prevention (CDC). Pertussis frequently asked questions. http://www.cdc.gov/pertussis/about/faqs.html. Updated December 19, 2013. Accessed August 14, 2014.

2. Centers for Disease Control and Prevention (CDC). Childhood whooping cough vaccine protects most children for at least 5 years. http://www.cdc.gov/media/matte/2011/10_whooping_cough.pdf. Updated December 18, 2013. Accessed August 14, 2014.

3. Centers for Disease Control and Prevention (CDC). Pertussis vaccination: clinical information for healthcare professionals. http://www.cdc.gov/pertussis/vaccines.html#clinical-information. Updated May 7, 2013. Accessed August 14, 2014.