Department of Paediatrics, L. Sacco Hospital, University of Milan, Italy.
Department of Paediatrics, L. Sacco Hospital, University of Milan, Italy.
Vaccine. 2014 Jan 23;32(5):527-34. doi: 10.1016/j.vaccine.2013.12.003. Epub 2013 Dec 14.
Few epidemiological data are available since the introduction of 13-valent pneumococcal vaccine (PCV13) in 2010. We conducted a cross-sectional study to estimate the prevalence of Streptococcus pneumoniae (SP) nasopharyngeal carriage in healthy Italian infants and young children and to evaluate the impact of PCV13 on pneumococcal colonization. In the trimester September-December 2011 nasopharyngeal swabs were collected from healthy children aged 3-59 months presenting for routine well careat 16 primary care pediatricians in Milan. SP carriage isolates were serotyped and tested for antimicrobial resistance using EUCAST breakpoints. Among 1250 enrolled children, 618 had received at least 1 dose of PCV13, 292 at least 1 dose of PCV7, 94 a combination of the two vaccines and 246 were not vaccinated. The prevalence of SP carriage was 27% (95% confidence interval [CI] 25-30). At multivariable analysis, age≥25 months (prevalence ratio [PR]=0.74) and use of antibiotics in the previous 3 months (PR=0.67) were associated with lower SP carriage prevalence. Having siblings (PR=1.79 for 1 sibling and PR=2.23 for ≥2 siblings), day-care attendance (PR=2.27) and respiratory tract infections in the previous 3 months (PR=1.39) were associated with higher SP carriage prevalence. The immunization status for SP was not associated with SP carriage at univariable or at multivariable analysis. The most common carriage isolates were 6C, 19A and 23A. The prevalence of the six additional PCV13 serotypes carriage in children appropriately vaccinated with PCV13 was lower than in children appropriately vaccinated with PCV7 (0 vs. 0.060); the greater reduction in prevalence of carriage was observed for serotype 19A (0 vs. 0.041). Serotype 6C was the most common drug-resistant serotype (17.2%). Further epidemiological studies are needed to assess changes in circulating SP serotypes following the large-scale introduction of PCV13.
自 2010 年 13 价肺炎球菌结合疫苗（PCV13）问世以来，仅有少量流行病学数据可用。我们进行了一项横断面研究，以评估意大利健康婴儿和幼儿中肺炎链球菌（SP）鼻咽携带的流行率，并评估 PCV13 对肺炎球菌定植的影响。在 2011 年 9 月至 12 月的三个月期间，从米兰的 16 位初级保健儿科医生处进行常规健康护理的 3-59 个月大的健康儿童中采集鼻咽拭子。使用 EUCAST 临界点对 SP 携带株进行血清分型和抗生素耐药性检测。在 1250 名入组儿童中，618 名至少接受过 1 剂 PCV13 接种，292 名至少接受过 1 剂 PCV7 接种，94 名接受过两种疫苗的联合接种，246 名未接种疫苗。SP 携带率为 27%（95%置信区间[CI]25-30）。多变量分析显示，年龄≥25 个月（比值比[PR]0.74）和前 3 个月使用抗生素（PR0.67）与 SP 携带率降低相关。有兄弟姐妹（有 1 个兄弟姐妹的 PR1.79，有≥2 个兄弟姐妹的 PR2.23）、日托出勤率（PR2.27）和前 3 个月发生呼吸道感染（PR1.39）与 SP 携带率升高相关。在单变量或多变量分析中，SP 免疫状态与 SP 携带均无相关性。最常见的携带分离株为 6C、19A 和 23A。在接受过 PCV13 适当接种的儿童中，六种额外 PCV13 血清型的携带率低于接受过 PCV7 适当接种的儿童（0 比 0.060）；19A 血清型的携带率下降更为显著（0 比 0.041）。血清型 6C 是最常见的耐药血清型（17.2%）。需要进一步开展流行病学研究，以评估 PCV13 大规模应用后循环 SP 血清型的变化。
