A Population-Based Study of Recurrent Symptomatic Bordetella pertussis Infections in Children in California, 2010-2015.

BACKGROUND: Natural infection with Bordetella pertussis is thought to result in 4-20 years of immunity against subsequent symptomatic pertussis infection. However, these estimates are based on studies in unvaccinated or whole-cell pertussis-vaccinated children. We conducted a population-based study of pertussis infection and reinfection during a 5-year period in California in an cohort vaccinated exclusively with acellular pertussis (aP) vaccine. METHODS: California 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 ≥2 episodes of symptomatic pertussis infection that met the case definition were included. RESULTS: Of 26259 pertussis cases reported in children (aged <18 years), 27 children met the inclusion criteria. Recurrent cases occurred among children of all ages; 5 (19%) were <6 months of age at the time of their first illness. The time from initial infection to reinfection was <1 year in 11 (41%) cases. Twenty-one children (78%) had received ≥3 doses of diphtheria and tetanus toxoids and aP vaccine at the time of their first pertussis infection, 1 (4%) had received 1 dose, and 5 (19%) were unvaccinated. CONCLUSIONS: 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.

Economic and Social Impact of Pertussis Among Adolescents in San Diego County.

PURPOSE: During recent pertussis epidemics, adolescents have experienced a large burden of disease. We assessed the impact of pertussis among San Diego adolescents and their households. METHODS: Parents of pertussis patients aged 13-17 years were surveyed about health care utilization, missed work and school, and other factors. Costs of medical visits, medication use, and lost wages were estimated. RESULTS: The parents of 53 (of 108 [49%]) eligible 2013 pertussis patients were interviewed; 51 (96%) of these patients previously received tetanus, diphtheria, and acellular pertussis vaccine. Medical visits included primary care (81%), urgent care (11%), and emergency department (9%); all patients received antibiotics. Forty-seven households (89%) received a post-exposure prophylaxis recommendation, and five (9%) reported ≥1 unpaid parental leave day. Thirty-eight patients (72%) missed ≥1 school day (mean = 5.4 days). Societal costs were estimated at $315.15 per household and $236,047.35 in San Diego during 2013-2014. CONCLUSIONS: Even among vaccinated adolescents, pertussis can result in considerable societal costs.