title: Lack of effectiveness of the 23-valent polysaccharide pneumococcal vaccine in reducing all-cause pneumonias among healthy young military recruits: a randomized, double-blind, placebo-controlled trial.
abstract: BACKGROUND
  Streptococcus pneumoniae infections have periodically caused significant morbidity and outbreaks among military personnel, especially trainees. This study evaluated the effectiveness of the 23-valent polysaccharide pneumococcal vaccine (PPV23) in reducing pneumonia in healthy military trainees.
  
  
  METHODS
  From 2000-2003, 152723 military trainees from 5 US training camps were enrolled in a double-blind, placebo-controlled trial of PPV23. Participants were closely monitored during basic training for radiographically confirmed pneumonia etiology and loss-of-training days. Participants were also followed using electronic medical encounter data until 1 June 2007 for three additional outcomes: any-cause pneumonia, any acute respiratory disease, and meningitis.
  
  
  RESULTS
  Comparison of demographic data by study arm suggested the randomization procedures were sound. During basic training, 371 study participants developed radiographically confirmed pneumonia. None had evidence of S. pneumoniae infection, but other etiologies included adenovirus (38%), Chlamydophila pneumoniae (9%), and Mycoplasma pneumoniae (8%). During the follow-up period, many study participants, in both the vaccine and placebo groups, had clinical encounters for the medical outcomes of interest. However, Cox's proportional hazard modeling revealed no evidence of a protective vaccine effect during recruit training (radiographically confirmed pneumonia) or up to 6.7 years after enrollment (any-cause pneumonia, any acute respiratory disease, or meningitis).
  
  
  CONCLUSIONS
  Data from this large, double-blind, placebo controlled trial do not support routine use of PPV23 among healthy new military trainees. This clinical trial was registered at clinicaltrials.gov (registration number NCT02079701, http://www.clinicaltrials.gov/ct2/show/NCT02079701?term=NCT02079701&rank=1).
authors.affiliation: Naval Health Research Center, Operational Infectious Diseases Department, 140 Sylvester Road, San Diego, CA 92106-3521, USA; Armed Forces Health Surveillance Center, 2900 Linden Lane, Silver Spring, MD 20901, USA. Electronic address: kevin.russell4@us.army.mil.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Russell
authors.affiliation: Naval Health Research Center, Operational Infectious Diseases Department, 140 Sylvester Road, San Diego, CA 92106-3521, USA; Hologic, Inc., 10210 Genetic Center Drive, San Diego, CA 92121, USA.
authors.forename: Carolyn I
authors.initials: CI
authors.lastname: Baker
authors.affiliation: Naval Health Research Center, Operational Infectious Diseases Department, 140 Sylvester Road, San Diego, CA 92106-3521, USA.
authors.forename: Christian
authors.initials: C
authors.lastname: Hansen
authors.affiliation: Mayo Vaccine Research Group, College of Medicine, 200 First Street, SW, Rochester, MN 55905, USA.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Poland
authors.affiliation: Naval Health Research Center, Operational Infectious Diseases Department, 140 Sylvester Road, San Diego, CA 92106-3521, USA; Clinical Investigation Program, Naval Hospital Camp Pendleton, H200 Room 4179, Camp Pendleton, CA 92055, USA.
authors.forename: Margaret A K
authors.initials: MA
authors.lastname: Ryan
authors.affiliation: Division of Infectious Diseases, Global Health Institute, & Nicholas School of the Environment, Duke University, 315 Trent Rd, Durham, NC 27710, USA.
authors.forename: Mary M
authors.initials: MM
authors.lastname: Merrill
authors.affiliation: Division of Infectious Diseases, Global Health Institute, & Nicholas School of the Environment, Duke University, 315 Trent Rd, Durham, NC 27710, USA. Electronic address: Gregory.gray@duke.edu.
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Gray
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008889:Military Personnel; D010919:Placebos / Q000008:administration & dosage; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D011014:Pneumonia / Q000453:epidemiology* / Q000517:prevention & control*; D055815:Young Adult
chemical_list: C414006:23-valent pneumococcal capsular polysaccharide vaccine; D010919:Placebos; D022242:Pneumococcal Vaccines
keywords: Epidemiology; Pneumococcus; Pneumonia; Streptococcus; Vaccine