Clinical Infectious Diseases (CID)
Volume 58 Issue 11 June 1, 2014
http://cid.oxfordjournals.org/content/current

Editorial Commentary: Pertussis Is Less Severe in Vaccinated Than in Unvaccinated Patients
Jussi Mertsola
Author Affiliations
Department of Pediatrics, Turku University Hospital and Turku University, Finland
Correspondence: Jussi Mertsola, MD, PhD, Department of Paediatrics and Adolescent Medicine, Turku University Hospital, 20520 Turku, Finland (See the Major Article by Barlow et al on pages 1523–9.)
Extract
After the introduction of vaccines against pertussis, there was a dramatic decrease of the disease, and the problem was considered to have been solved. But it was not. Recently, large outbreaks have occurred in the United States, in several European countries, and in Australia [1, 2]. It is evident that there are still many unresolved questions in pertussis, the first of which is that we do not know enough about the exact pathogenesis of this infection and the real appearance of Bordetella pertussis organisms in vivo. We also do not know much about the intracellular living of the bacteria and possible transition between the virulent and nonvirulent phenotypes in the mucosal environment in the lungs. Perhaps we should again pay more attention to the old questions of molecular mimicry [3]. The infection cascade is very complex, and immunity is multifactorial. During and after the development of the acellular vaccine, the main focus has been on the extracellular living of B. pertussis and humoral immunity. In pertussis, the function of Th1 and Th17 cells seems to be very important [4]. Surprisingly, even some 100 years after the discovery of B. pertussis, we do not even understand the exact mechanism behind the typical paroxysmal cough in whooping cough.
Young infants are most vulnerable if they get B. pertussis infection. Historically, pertussis has been a serious killer, and recent outbreaks show that infants have a real risk of death and complications even today [1, 2]. One of the main problems is how to induce immunity against pertussis in young infants. The situation was so alarming in California in 2012 and in the United Kingdom that vaccinations against tetanus, diphtheria, and pertussis…

Vaccinated Children and Adolescents With Pertussis Infections Experience Reduced Illness Severity and Duration, Oregon, 2010–2012
Russell S. Barlow, Laura E. Reynolds, Paul R. Cieslak, and Amy D. Sullivan
Clin Infect Dis. (2014) 58 (11): 1523-1529 doi:10.1093/cid/ciu156
Abstract
We examined how vaccination status influenced the course of illness among persons infected with Bordetella pertussis in Oregon between 2010 and 2012. Our analyses provide evidence that vaccinated individuals have decreased disease severity and reduced illness duration.