title: Boosting Immune Responses Following Fractional-Dose Inactivated Poliovirus Vaccine: A Randomized, Controlled Trial.
abstract: BACKGROUND
  Fractional-dose administration of inactivated poliovirus vaccine (fIPV) could increase IPV affordability and stretch limited supplies. We assessed immune responses following fIPV administered intradermally, compared with full-dose IPV administered intramuscularly, among adults with a history of oral poliovirus vaccine (OPV) receipt.
  
  
  METHODS
  We conducted a randomized, controlled noninferiority trial in Cuba. fIPV or IPV were administered on days 0 and 28; serum was collected on days 0, 7, 28, and 56 for analysis by a neutralization assay. The primary end point was seroconversion or a ≥4-fold rise in antibody titer. The noninferiority limit was 10%. The secondary end point was safety, assessed by the number and intensity of adverse reactions.
  
  
  RESULTS
  A total of 503 of 534 enrolled participants (94.2%) completed all study requirements. Twenty-eight days after the first dose, 94.8%, 98.0%, and 98.0% of fIPV recipients had an immune response to poliovirus types 1, 2, and 3, respectively, compared with 98.1% (P = .06), 98.0% (P = 1.00), and 99.2% (P = .45) in the IPV arm. Noninferiority was achieved on days 7, 28, and 56 for all serotypes. No serious adverse events were reported.
  
  
  CONCLUSIONS
  fIPV induced similar boosting immune responses, compared with full-dose IPV. This suggests that fIPV would be an effective strategy to boost population immunity in an outbreak situation.
  
  
  BACKGROUND
  ACTRN12615000305527.
authors.affiliation: Pedro Kouri Institute of Tropical Medicine, Havana.
authors.forename: Sonia
authors.initials: S
authors.lastname: Resik
authors.affiliation: Provincial Center for Hygiene, Epidemiology, and Microbiology, Camaguey, Cuba.
authors.forename: Alina
authors.initials: A
authors.lastname: Tejeda
authors.affiliation: Pedro Kouri Institute of Tropical Medicine, Havana.
authors.forename: Manuel
authors.initials: M
authors.lastname: Diaz
authors.affiliation: World Health Organization, Geneva, Switzerland.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Okayasu
authors.affiliation: World Health Organization, Geneva, Switzerland.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Sein
authors.affiliation: World Health Organization, Geneva, Switzerland.
authors.forename: Natalie A
authors.initials: NA
authors.lastname: Molodecky
authors.affiliation: Pedro Kouri Institute of Tropical Medicine, Havana.
authors.forename: Magile
authors.initials: M
authors.lastname: Fonseca
authors.affiliation: Provincial Center for Hygiene, Epidemiology, and Microbiology, Camaguey, Cuba.
authors.forename: Nilda
authors.initials: N
authors.lastname: Alemany
authors.affiliation: Provincial Center for Hygiene, Epidemiology, and Microbiology, Camaguey, Cuba.
authors.forename: Gloria
authors.initials: G
authors.lastname: Garcia
authors.affiliation: Pedro Kouri Institute of Tropical Medicine, Havana.
authors.forename: Lai Heng
authors.initials: LH
authors.lastname: Hung
authors.affiliation: Pedro Kouri Institute of Tropical Medicine, Havana.
authors.forename: Yenisleydis
authors.initials: Y
authors.lastname: Martinez
authors.affiliation: World Health Organization, Geneva, Switzerland.
authors.forename: Roland W
authors.initials: RW
authors.lastname: Sutter
mesh_terms: D000293:Adolescent; D000328:Adult; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D003462:Cuba; D006801:Humans; D007117:Immunization, Secondary / Q000009:adverse effects / Q000379:methods*; D007271:Injections, Intradermal; D007273:Injections, Intramuscular; D008297:Male; D009500:Neutralization Tests; D011051:Poliomyelitis / Q000276:immunology / Q000517:prevention & control*; D011054:Poliovirus Vaccine, Inactivated / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D011054:Poliovirus Vaccine, Inactivated
keywords: IPV; boost; boosting; fractional dose; inactivated poliovirus vaccine; poliovirus