Has the DTaP vaccine caused the increase in whooping cough?

Max-Vax adherents have been blaming the recent pertussis (“whooping cough”) outbreak in California on unvaccinated children, rather than addressing with the public the known reality: the outbreak occurred because the DTaP (Diptheria, Tetanus, and acellular Pertussis) vaccine is not effective. It is true that some parents are not vaccinating their children with the DTaP vaccine because of the high risk of vaccine-injury estimated as a 1 in 13 risk of asthma (see Vaccine-Induced Asthma), which is far higher than the risk from the disease (see Disease Risk – Pertussis).

But this is not the cause of the outbreak, as public health officials know:

  • The CDC reports that in the United States, cases of whooping cough have increased approximately 10-fold in the last twenty years [1], despite an increase in infant vaccination rates from 61% getting at least three doses of the pertussis vaccine in 1991 to 96.2% getting at least three doses in 2008 [2].
  • In a report on a small 2009 whooping cough cluster in Atlanta, the CDC admitted that a better pertussis vaccine is needed (HERE)
  • A 2010 Penn State study found that DTaP vaccination actually enhances the growth of parapertussis bacteria, which can cause a typically milder strain of whooping cough.  The DTaP vaccine only vaccinates against pertussis, not parapertussis. Counts of whooping cough include the total of cases caused from pertussis bacteria and parapertussis bacteria.  This study indicates that the DTaP vaccine has caused a rise in overall whooping cough cases (due to the rise in parapertussis) since its introduction in the USA in 1996 (see Acellular pertussis vaccination enhances B. parapertussis colonization).
  • Pertussis vaccines don’t protect against pertussis infection, but do appear to reduce risk of death and severity of the disease if infected.  This Pertussis Vaccine Effectiveness study found that “In this study, 60% of pertussis cases were among children who had received >= 3 pertussis vaccine doses. Although protective against death and severe morbidity, pertussis vaccines are imperfect; after receipt of  >= 3 doses, vaccinees can still become infected and symptomatic after significant exposure to B pertussis.”
  • An Israeli study indicates that asymptomatic vaccinated children can be carriers of whooping cough bacteria (HERE).  Interpreting this data and considering the extremely low percentage of unvaccinated children, this means the 2010 outbreak in California must mathematically be attributable to the vaccinated children spreading the bacteria.
  • · Per the NY Times, “The rise in pertussis doesn’t seem to be related to parents’ refusing to have their children vaccinated for fear of potential side effects. In California, pertussis rates are about the same in counties with high childhood vaccination rates and low ones.” (HERE)

For thoughtful discussion on what’s really occurring with the California pertussis outbreak and the need for a more effective and safer pertussis vaccine, see:



[1] Centers for Disease Control and Prevention. Pertussis- United States; 2001-2003. Found at www.cdc.gov.

[2] Guris D, Strebel P, Bardenheier B, Brennan M, Tachdjian R, Finch E, Wharton M, Livengood J. Changing Epidemeology of Pertussis in the United States: Increasing Reported Incidence Among Adolescents and Adults, 1990-1996. Clin Infect Diseases. 1998. 28: 1230-7.