title: Early Changes in the Serotype Distribution of Invasive Pneumococcal Isolates from Children after the Introduction of Extended-valent Pneumococcal Conjugate Vaccines in Korea, 2011-2013.
abstract: This study was performed to measure early changes in the serotype distribution of pneumococci isolated from children with invasive disease during the 3-year period following the introduction of 10- and 13-valent pneumococcal conjugate vaccines (PCVs) in Korea. From January 2011 to December 2013 at 25 hospitals located throughout Korea, pneumococci were isolated among children who had invasive pneumococcal disease (IPD). Serotypes were determined using the Quellung reaction, and the change in serotype distribution was analyzed. Seventy-five cases of IPD were included. Eighty percent of patients were aged 3-59 months, and 32% had a comorbidity that increased the risk of pneumococcal infection. The most common serotypes were 19A (32.0%), 10A (8.0%), and 15C (6.7%). The PCV7 serotypes (4, 6B, 9V, 14, 18C, 19F, 23F, and 6A) accounted for 14.7% of the total isolates and the PCV13 minus PCV7 types (1, 3, 5, 7F and 19A) accounted for 32.0% of the total isolates. Serotype 19A was the only serotype in the PCV13 minus PCV7 group. The proportion of serotype 19A showed decreasing tendency from 37.5% in 2011 to 22.2% in 2013 (P = 0.309), while the proportion of non-PCV13 types showed increasing tendency from 45.8% in 2011 to 72.2% in 2013 (P = 0.108). Shortly after the introduction of extended-valent PCVs in Korea, serotype 19A continued to be the most common serotype causing IPD in children. Subsequently, the proportion of 19A decreased, and non-vaccine serotypes emerged as an important cause of IPD. The impact of extended-valent vaccines must be continuously monitored.
authors.affiliation: Seoul National University College of Medicine, Seoul, Korea.; Chungnam National University Hospital, Daejeon, Korea.
authors.forename: Eun Young
authors.identifier: 0000-0002-2286-4593
authors.initials: EY
authors.lastname: Cho
authors.affiliation: Seoul National University College of Medicine, Seoul, Korea .
authors.forename: Eun Hwa
authors.identifier: 0000-0002-5857-0749
authors.initials: EH
authors.lastname: Choi
authors.affiliation: College of Medicine, the Catholic University of Korea, Seoul, Korea .
authors.forename: Jin Han
authors.identifier: 0000-0003-1610-6742
authors.initials: JH
authors.lastname: Kang
authors.affiliation: School of Medicine, Ewha Womans University, Seoul, Korea .
authors.forename: Kyung-Hyo
authors.identifier: 0000-0002-0333-6808
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Yonsei University College of Medicine, Seoul, Korea .
authors.forename: Dong Soo
authors.identifier: 0000-0002-3270-506X
authors.initials: DS
authors.lastname: Kim
authors.affiliation: Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea .
authors.forename: Yae-Jean
authors.identifier: 0000-0002-8367-3424
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Eulji University School of Medicine, Daejeon, Korea .
authors.forename: Young Min
authors.identifier: 0000-0002-1697-8041
authors.initials: YM
authors.lastname: Ahn
authors.affiliation: Eulji University School of Medicine, Daejeon, Korea .
authors.forename: Byung Wook
authors.identifier: 0000-0003-3147-9061
authors.initials: BW
authors.lastname: Eun
authors.affiliation: Hanyang University, College of Medicine, Seoul, Korea .
authors.forename: Sung Hee
authors.identifier: 0000-0001-6943-5430
authors.initials: SH
authors.lastname: Oh
authors.affiliation: Kyung Hee University School of Medicine, Seoul, Korea .
authors.forename: Sung-Ho
authors.identifier: 0000-0003-0540-5747
authors.initials: SH
authors.lastname: Cha
authors.affiliation: Graduate School of Medicine, Gachon University, Incheon, Korea .
authors.forename: Hye-Kyung
authors.identifier: 0000-0003-0990-1350
authors.initials: HK
authors.lastname: Cho
authors.affiliation: Inha University School of Medicine, Incheon, Korea .
authors.forename: Young Jin
authors.identifier: 0000-0002-0878-9515
authors.initials: YJ
authors.lastname: Hong
authors.affiliation: Hallym University College of Medicine, Chuncheon, Korea .
authors.forename: Kwang Nam
authors.identifier: 0000-0003-4024-5128
authors.initials: KN
authors.lastname: Kim
authors.affiliation: Inje University College of Medicine, Seoul, Korea .
authors.forename: Nam Hee
authors.identifier: 0000-0002-1793-1392
authors.initials: NH
authors.lastname: Kim
authors.affiliation: Korea University College of Medicine, Seoul, Korea .
authors.forename: Yun-Kyung
authors.identifier: 0000-0003-4396-8671
authors.initials: YK
authors.lastname: Kim
authors.affiliation: College of Medicine, the Catholic University of Korea, Seoul, Korea .
authors.forename: Jong-Hyun
authors.identifier: 0000-0001-8641-7904
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Seoul National University Bundang Hospital, Seoul, Korea .
authors.forename: Hyunju
authors.identifier: 0000-0003-0107-0724
authors.initials: H
authors.lastname: Lee
authors.affiliation: CHA Bundang Medical Center, CHA University, Seoul, Korea .
authors.forename: Taekjin
authors.identifier: 0000-0002-8912-6982
authors.initials: T
authors.lastname: Lee
authors.affiliation: Yonsei University Wonju College of Medicine, Wonju, Korea .
authors.forename: Hwang Min
authors.identifier: 0000-0002-0329-1371
authors.initials: HM
authors.lastname: Kim
authors.affiliation: College of Medicine, Dankook University, Cheonan, Korea .
authors.forename: Kun Song
authors.identifier: 0000-0001-7318-2296
authors.initials: KS
authors.lastname: Lee
authors.affiliation: Keimyung University School of Medicine, Daegu, Korea .
authors.forename: Chun Soo
authors.identifier: 0000-0003-3888-334X
authors.initials: CS
authors.lastname: Kim
authors.affiliation: Pusan National University School of Medicine, Busan, Korea .
authors.forename: Su Eun
authors.identifier: 0000-0001-5860-821X
authors.initials: SE
authors.lastname: Park
authors.affiliation: Pusan National University School of Medicine, Busan, Korea .
authors.forename: Young Mi
authors.identifier: 0000-0002-6853-2228
authors.initials: YM
authors.lastname: Kim
authors.affiliation: Kosin University College of Medicine, Busan, Korea .
authors.forename: Chi Eun
authors.identifier: 0000-0002-0439-8170
authors.initials: CE
authors.lastname: Oh
authors.affiliation: Changwon Fatima Hospital, Changwon, Korea .
authors.forename: Sang Hyuk
authors.identifier: 0000-0002-0582-9286
authors.initials: SH
authors.lastname: Ma
authors.affiliation: Chonbuk National University Medical School, Jeonju, Korea .
authors.forename: Dae Sun
authors.identifier: 0000-0002-3141-9539
authors.initials: DS
authors.lastname: Jo
authors.affiliation: Chonnam National University Medical School, Gwangju, Korea .
authors.forename: Young Youn
authors.identifier: 0000-0002-8631-8241
authors.initials: YY
authors.lastname: Choi
authors.affiliation: University of Ulsan College of Medicine, Seoul, Korea .
authors.forename: Jina
authors.identifier: 0000-0002-3435-251X
authors.initials: J
authors.lastname: Lee
authors.affiliation: Korea Centers for Disease Control and Prevention, Cheongju, Korea .
authors.forename: Geun-Ryang
authors.identifier: 0000-0002-4429-1378
authors.initials: GR
authors.lastname: Bae
authors.affiliation: Korea Centers for Disease Control and Prevention, Cheongju, Korea .
authors.forename: Ok
authors.identifier: 0000-0002-9477-9523
authors.initials: O
authors.lastname: Park
authors.affiliation: Korea Centers for Disease Control and Prevention, Cheongju, Korea .
authors.forename: Young-Joon
authors.identifier: 0000-0001-9697-4173
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Korea Centers for Disease Control and Prevention, Cheongju, Korea .
authors.forename: Eun Seong
authors.identifier: 0000-0002-8621-0396
authors.initials: ES
authors.lastname: Kim
authors.affiliation: Seoul National University College of Medicine, Seoul, Korea .
authors.forename: Hoan Jong
authors.identifier: 0000-0001-9643-3692
authors.initials: HJ
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D016470:Bacteremia / Q000150:complications / Q000175:diagnosis; D002648:Child; D002675:Child, Preschool; D005260:Female; D006761:Hospitals; D006801:Humans; D007223:Infant; D008297:Male; D011008:Pneumococcal Infections / Q000382:microbiology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000276:immunology*; D056910:Republic of Korea; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000302:isolation & purification; D018074:Vaccines, Conjugate / Q000276:immunology*
chemical_list: C538862:13-valent pneumococcal vaccine; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate
keywords: Pneumococcal Vaccines; Serotype; Streptococcus pneumoniae