BACKGROUND: Asymptomatic nasopharyngeal carriage is the main reservoir for transmission of Streptococcus pneumoniae. The rate of both carriage and pneumococcal disease decreases with age. To what extent these changes are the result of developing natural immunity is currently a subject of debate. OBJECTIVE: To study the hypothesis that previous carriage induces serotype-independent protective immunity to new colonization. METHODS: We compared the rates of pneumococcal acquisition for children with different previous carriage histories. We identified 435 episodes of carriage during the first year of life in follow-up data for 99 Bangladeshi children. Cox regression analysis was adjusted for serotype-specific exposure within the family and other confounding factors. RESULTS: Previous pneumococcal carriage was associated with serotype-independent protection from subsequent acquisition (hazard ratio, 0.60 [95% confidence interval, 0.39-0.90]), whereas recent serotype-specific exposure within the family was associated with an 8-fold increase in the rate of acquisition for that serotype. CONCLUSION: Our findings are consistent with the hypothesis that serotype-independent protective immunity is stimulated in young children by previous pneumococcal carriage and reduces the rate of new colonization. This immunity has the potential to modulate the development of carriage, irrespective of the colonizing serotype, and to do so starting early in infancy.
BACKGROUND: Asymptomatic nasopharyngeal carriage is the main reservoir for transmission of Streptococcus pneumoniae. The rate of both carriage and pneumococcal disease decreases with age. To what extent these changes are the result of developing natural immunity is currently a subject of debate. OBJECTIVE: To study the hypothesis that previous carriage induces serotype-independent protective immunity to new colonization. METHODS: We compared the rates of pneumococcal acquisition for children with different previous carriage histories. We identified 435 episodes of carriage during the first year of life in follow-up data for 99 Bangladeshi children. Cox regression analysis was adjusted for serotype-specific exposure within the family and other confounding factors. RESULTS: Previous pneumococcal carriage was associated with serotype-independent protection from subsequent acquisition (hazard ratio, 0.60 [95% confidence interval, 0.39-0.90]), whereas recent serotype-specific exposure within the family was associated with an 8-fold increase in the rate of acquisition for that serotype. CONCLUSION: Our findings are consistent with the hypothesis that serotype-independent protective immunity is stimulated in young children by previous pneumococcal carriage and reduces the rate of new colonization. This immunity has the potential to modulate the development of carriage, irrespective of the colonizing serotype, and to do so starting early in infancy.
Authors: Marc Lipsitch; Osman Abdullahi; Alexander DʼAmour; Wen Xie; Daniel M Weinberger; Eric Tchetgen Tchetgen; J Anthony G Scott Journal: Epidemiology Date: 2012-07 Impact factor: 4.822
Authors: Anna Lundgren; Taufiqur R Bhuiyan; Daniel Novak; Joanna Kaim; Adi Reske; Ying-Jie Lu; Firdausi Qadri; Richard Malley Journal: Vaccine Date: 2012-04-12 Impact factor: 3.641
Authors: Elsa N Bou Ghanem; Nang H Tin Maung; Nalat Siwapornchai; Aaron E Goodwin; Stacie Clark; Ernesto J Muñoz-Elías; Andrew Camilli; Rachel M Gerstein; John M Leong Journal: J Immunol Date: 2018-04-16 Impact factor: 5.422
Authors: Alessia Melegaro; Yoon Hong Choi; Robert George; W John Edmunds; Elizabeth Miller; Nigel J Gay Journal: BMC Infect Dis Date: 2010-04-08 Impact factor: 3.090