Pasinato Angela, Indolfi Giuseppe, Marchisio Paola, Valleriani Claudia, Cortimiglia Martina, Spanevello Valter, Chiamenti Giampietro, Buzzetti Roberto, Resti Massimo, Azzari Chiara
Center for Research and Education of Family Pediatricians (CESPER), via Gozzi 24, 35131 Padova, Italy.
Department of Paediatrics, University of Florence, Meyer Children's University-Hospital, Viale Pieraccini 24, Firenze, Italy.
Vaccine. 2014 Mar 10;32(12):1375-81. doi: 10.1016/j.vaccine.2014.01.023. Epub 2014 Jan 28.
The long term impact of 7-valent pneumococcal conjugate vaccine (PCV7) on pneumococcal colonization patterns remains unclear. Carriage and distribution of Streptococcus pneumoniae serotypes as detected by RT-PCR were evaluated in a cohort of 1315 children. S. pneumoniae was identified in the nasopharyngeal swab of 734 children (55.8%); 488/734 (66.5%) children carried more than 1 pneumococcal serotype. As a consequence of co-colonization, a total of 1,728 S. pneumoniae (belonging to 33 serotypes) were identified. As immunogenicity between 2 and 3 doses of PCV7 in the first year of life has been demonstrated to be similar, serotypes distribution was evaluated categorizing vaccination status as 0,1 and 2 or more doses in the first year of life. Among children who started vaccination in the first year of life, PCV7 serotypes were carried in 296 of 1,123 (29.5%) children who had received ≥2 PCV7 doses while were carried in 26 of 108 (26.8%) who had received no doses (p=not significant); only 17 children received 1 PCV7 and 3 of them were found positive for PCV7 serotypes. Among those who had received ≥2 doses of PCV7 in the first year of life, 47 of 192 (19.7%) carried a PCV7 serotype during the first year after last vaccination, 50 of 125 (28.6%) during the second year, 79 of 224 (35.3%) during the third year, and 65 of 143 (45.5%) during the fourth year (p 0.0001). We did not identify risk factors for PCV7 carriage among children that had received >2 vaccine doses. This study suggests that S. pneumoniae is present in the nasopharynx of the majority of children 0-5 years even if vaccinated, that PCV7 serotypes can be found in nasopharyngeal swabs of PCV7 vaccinated children and that the frequency of PCV7 serotypes increases with the increase of interval from vaccination.
7价肺炎球菌结合疫苗（PCV7）对肺炎球菌定植模式的长期影响尚不清楚。通过逆转录聚合酶链反应（RT-PCR）检测，对1315名儿童队列中的肺炎链球菌血清型的携带和分布情况进行了评估。在734名儿童（55.8%）的鼻咽拭子中鉴定出肺炎链球菌；488/734名（66.5%）儿童携带不止1种肺炎球菌血清型。由于共同定植，总共鉴定出1728株肺炎链球菌（属于33种血清型）。由于已证明在生命的第一年接种2剂和3剂PCV7之间的免疫原性相似，因此将疫苗接种状态分类为生命第一年接种0剂、1剂以及2剂或更多剂，对血清型分布进行了评估。在生命第一年开始接种疫苗的儿童中，在1123名接受≥2剂PCV7的儿童中有296名（29.5%）携带PCV7血清型，而在108名未接种疫苗的儿童中有26名（26.8%）携带PCV7血清型（p值无统计学意义）；只有17名儿童接种了1剂PCV7，其中3名被发现PCV7血清型呈阳性。在生命第一年接受≥2剂PCV7的儿童中，在最后一次接种后的第一年，192名中有47名（占19.7%）携带PCV7血清型，第二年125名中有50名（占28.6%），第三年224名中有79名（占35.3%），第四年143名中有65名（占45.5%）（p<0.0001）。我们未在接受>2剂疫苗的儿童中确定PCV7携带的危险因素。本研究表明，即使接种了疫苗，0至5岁的大多数儿童的鼻咽部仍存在肺炎链球菌，在接种PCV7的儿童的鼻咽拭子中可发现PCV7血清型，并且PCV7血清型的频率随着接种间隔时间的增加而升高。
