title: Early impact of sequential introduction of 7-valent and 13-valent pneumococcal conjugate vaccine on IPD in Israeli children <5 years: an active prospective nationwide surveillance.
abstract: BACKGROUND
  The 7-valent pneumococcal conjugated vaccine (PCV7) was introduced to the Israeli national immunization plan (NIP) in July 2009 (administered at age 2, 4 and 12 months), with a fast reduction of invasive pneumococcal disease (IPD) caused by PCV7 serotypes. Starting in November 2010, PCV13 gradually replaced PCV7.
  
  
  OBJECTIVE
  To report the impact of PCV7/PCV13 sequential introduction on IPD in Israeli children <5 years.
  
  
  METHODS
  An ongoing nationwide, prospective, population-based, active surveillance. All IPD episodes (Streptococcus pneumoniae isolated from blood and/or cerebrospinal fluid) from July 2004 through June 2013 were included.
  
  
  RESULTS
  Overall, 2670 IPD episodes were recorded. Incidence of IPD caused by PCV7+6A serotypes during the PCV13 period vs. pre-PCV period decreased by 95% (Incidence Rate Ratio [IRR]=0.05; 95% CI=0.03-0.09). This reduction was observed in a two-step manner: 90% in the PCV7-period and further 5% in the PCV13-period. The rates of IPD caused by the 5 additional PCV13-serotypes (1, 3, 5, 7F, 19A; 5VT) increased initially by 47%, but subsequently decreased by 79%, resulting in an overall 70% reduction during the entire study period (IRR=0.30; 0.21-0.44). A two-fold increase in non-PCV13 serotypes IPD was observed (IRR=2.43; 1.73-3.66). In total, a 63% reduction of all-serotype IPD episodes was observed in children <5 years (69% and 48% in children <2 and 2-4 years old, respectively).
  
  
  CONCLUSIONS
  After initiation of PCV NIP, a rapid and substantial 2-step IPD reduction was observed in children <5 years. The serotype-specific rate reduction reflected the sequential introduction of PCV7/PCV13.
authors.affiliation: The Pediatric Infectious Disease Unit, Soroka University Medical Center, Ben-Gurion University, Beer-Sheva, Israel.
authors.forename: Shalom
authors.initials: S
authors.lastname: Ben-Shimol
authors.affiliation: The Pediatric Infectious Disease Unit, Soroka University Medical Center, Ben-Gurion University, Beer-Sheva, Israel.
authors.forename: David
authors.initials: D
authors.lastname: Greenberg
authors.affiliation: The Pediatric Infectious Disease Unit, Soroka University Medical Center, Ben-Gurion University, Beer-Sheva, Israel.
authors.forename: Noga
authors.initials: N
authors.lastname: Givon-Lavi
authors.affiliation: Shaare Zedek Medical Center, Jerusalem, Israel.
authors.forename: Yechiel
authors.initials: Y
authors.lastname: Schlesinger
authors.affiliation: Wolfson Medical Center, Holon, Israel.
authors.forename: Eli
authors.initials: E
authors.lastname: Somekh
authors.affiliation: The Barzilai Medical Center, Ashkelon, Israel.
authors.forename: Shraga
authors.initials: S
authors.lastname: Aviner
authors.affiliation: The Pediatric Infectious Disease Service, HaEmek Medical Center, Afula, Israel.
authors.forename: Dan
authors.initials: D
authors.lastname: Miron
authors.affiliation: The Pediatric Infectious Disease Unit, Soroka University Medical Center, Ben-Gurion University, Beer-Sheva, Israel. Electronic address: rdagan@bgu.ac.il.
authors.forename: Ron
authors.initials: R
authors.lastname: Dagan
mesh_terms: D002675:Child, Preschool; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D015994:Incidence; D007223:Infant; D007557:Israel / Q000453:epidemiology; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D011446:Prospective Studies; D018571:Sentinel Surveillance; D018074:Vaccines, Conjugate / Q000008:administration & dosage
chemical_list: C538862:13-valent pneumococcal vaccine; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate
keywords: Children; Invasive pneumococcal disease (IPD); Pneumococcal conjugate vaccine (PCV); Surveillance