This case was reported in a literature article and described the occurrence of vaccination failure in a child male subject who received DTPa vaccine. On an unknown date, unknown after receiving DTPa vaccine, DTPa vaccine, DTPa vaccine and DTPa vaccine, 5 years and 127 days after receiving DTPa vaccine and not applicable after receiving dTpa vaccine, the subject developed vaccination failure. Serious criteria included GSK medically significant. Additional event(s) included pertussis with serious criteria of GSK medically significant, vaccination failure with serious criteria of GSK medically significant, pertussis with serious criteria of GSK medically significant, cough, paroxysmal cough and vomiting. The outcome of the  vaccination failure was recovered/resolved. The outcome(s) of the additional event(s) included pertussis (recovered/resolved), vaccination failure (unknown), pertussis (unknown), cough (recovered/resolved), paroxysmal cough (unknown) and vomiting (unknown). The investigator considered that there was a reasonable possibility that the vaccination failure, pertussis, vaccination failure, pertussis, cough, paroxysmal cough and vomiting may have been caused by DTPa vaccine, DTPa vaccine, DTPa vaccine, DTPa vaccine and DTPa vaccine. The investigator considered that there was a reasonable possibility that the vaccination failure, pertussis, paroxysmal cough and vomiting may have been caused by dTpa vaccine. Relevant Tests: Lab tests performed on an unspecified dates between 1 January 2010 and 31 December 2015. At the age between 4-10 years, the patient was detected with B. pertussis-specific nucleic acid by PCR and diagnosed with Bordetella pertussis infection. At the age between 11 and 17 years, the patient was detected with B. pertussis-specific nucleic acid by PCR and diagnosed with recurrent Bordetella pertussis infection. Diagnostic results (unless otherwise stated, normal values were not provided): On an unknown date, Bordetella test positive result was see text unknown. On an unknown date, Polymerase chain reaction result was see text unknown. Additional information was provided. This case was reported in a literature article and described the vaccination failure in a male patient aged between 4-10 years who was vaccinated with unspecified Tdap vaccine and unspecified DTaP vaccine (manufacturer unknown for both). The patient was a part of a population-based study of pertussis infection and reinfection conducted during a 5-year period in an cohort vaccinated exclusively with acellular pertussis (aP) vaccine. In this study, the surveillance data were reviewed to identify all children with 2 reported incidents of pertussis with symptom onset between 1 January 2010 and 31 December 2015. Case investigation reports were reviewed, and children with greater than and equal to 2 episodes of symptomatic pertussis infection that met the case definition were included. In this study,confirmed and probable pertussis cases are defined in accordance with the 2010 and 2014 criteria from the Council. Suspected cases were characterized by either an acute cough illness of any duration along with detection of B. pertussis-specific nucleic acid by polymerase chain reaction (PCR) or an acute cough illness of any duration and greater than and equal to 1 of the following: paroxysms of cough, inspiratory "whoop", or post-tussive vomiting. The suspected case classification is unique and was created to capture patients with pertussis who met the criteria for a confirmed case but had not coughed greater than and equal to 2 weeks at the time of interview. In total, 27 children with 2 distinct episodes of pertussis were included in this study. The majority of cases had greater than and equal to 1 incident with onset in 2014 or 2015 during a major pertussis epidemic. None of the children had an immunocompromising condition diagnosed. No information on medical or family history or concomitant medication was provided. On unspecified dates, the patient had received 5 doses of unspecified DTaP vaccine (administration route and site unspecified; batch number not provided). The age of vaccinations was not provided. On an unspecified date, between 1 January 2010 and 31 December 2015, at the age between 4-10 years, 5.4 years after the 5th dose of DTaP vaccine, the patient had experienced cough. The cough duration was more than equal to 14 days. The patient was detected with B. pertussis-specific nucleic acid by PCR and diagnosed with Bordetella pertussis infection. Later, on an unspecified date, the patient had received 1 dose of unspecified Tdap vaccine (administration route and site unspecified; batch number not provided). The age of vaccination was not provided. On an unspecified date, at the age between 11 and 17 years, 2.6 years after the Tdap dose and 3.9 years after the last pertussis episode, the patient had experienced paroxysmal cough, whoop and vomiting. The duration of cough was more than equal to 14 days. The patient was detected with B. pertussis-specific nucleic acid by PCR and diagnosed with recurrent Bordetella pertussis infection. (In this study, four children visited the emergency room for their pertussis illness: 1 during the first pertussis episode, 2 during the second episode, and 1 for both episodes). This case has been considered as vaccination failure. This case has been considered serious due to vaccination failure. Treatment was unknown. The outcome of the event was not reported. The authors comment on the relationship between the events and unspecified DTaP and Tdap vaccines 'Unfortunately, owing to the small number of cases identified in the current study, it was not possible to determine whether priming with aP vaccine made it more or less likely that children would experience a second pertussis episode'. The authors additionally stated 'Given our findings, we propose 4 hypotheses to explain the occurrence of recurrent symptomatic pertussis episodes. First, it is possible that priming with aP vaccines might affect the ability of a child to mount a sterilizing immune response after natural infection when compared to a naive or wP-vaccinated child. This hypothesis is supported by reports in the literature indicating that priming with aP vaccine might result in linked epitope suppression and a skewed Th2 response compared with the Th1- and Th1 7 response associated with wP vaccination and natural infection. However, the link between these immune modulations and decreased protection against pertussis colonization and/or disease has not been established. Second, it is possible that the children in our study may have unidentified host factors making them uniquely susceptible to pertussis. However, all medical records were reviewed, none of the children had a previously diagnosed immunocompromising condition, and all but 1 were noted to be otherwise healthy. The third hypothesis is that the children included in this study might have been coinfected with another respiratory pathogen at the time they were diagnosed with pertussis. If this is true, it is possible that it was the other respiratory pathogen that caused the cough illness and that they may have only been asymptomatically infected with B. pertussis. Finally, it is possible that these cases represent examples of latent colonization and reactivation of B. pertussis. This hypothesis is not favored given the overwhelming evidence against latent and chronic carriage of B. pertussis. Unfortunately, the results from this study cannot help discriminate between these various possibilities. The majority of episodes (69%) included in this study occurred during 2014 and 2015. It is possible that having 2 back-to-back high-transmission years led to more opportunity for exposure to B. pertussis in a fairly short time interval. Since the implementation of routine pertussis vaccination, the reduced opportunity for continual subclinical transmission and subsequent boosting has resulted in waning immunity and increased rates of pertussis in adolescents and adults'. The authors concluded "Recurrent cases of pertussis infection are extremely rare. Based on this surveillance data, approximately 0.1% of children who were infected with pertussis experienced a clinically significant second episode of pertussis within 4 years. More research is needed to understand the immune response to B. pertussis infection in children vaccinated with aP vaccines. In conclusion, despite its limitations, our study is the first population-based study to document laboratory-confirmed recurrent pertussis episodes in children in the aP vaccine era. Our findings showed that, although rare, recurrent cases of pertussis can occur, and in 1 instance the second episode occurred as early as 89 days after onset of the first episode. We also show that recurrent cases occur among children of all ages and among children who had received more than equal to 3 doses of aP vaccine. The identification of recurrent cases of pertussis in children raises important questions about the duration and nature of immunity provided by natural infection in aP-vaccinated, and unvaccinated children. In particular, a better understanding of how priming with aP vaccine might affect the immune response after exposure to B. pertussis is needed". This is 1 of the 26 valid cases reported in the same literature article.