title: Effect of multiple, simultaneous vaccines on polio seroresponse and associated health outcomes.
abstract: BACKGROUND
  Administration of multiple simultaneous vaccines to infants, children, and military recruits is not uncommon. However, little research exists to examine associated serological and health effects, especially in adults.
  
  
  METHODS
  We retrospectively examined 416 paired serum specimens from U.S. military subjects who had received the inactivated polio vaccine (IPV) alone or in combination with either 1 other vaccine (<3 group) or 4 other vaccines (>4 group). Each of the 2 groups was subdivided into 2 subgroups in which Tdap was present or absent.
  
  
  RESULTS
  The >4 group was associated with a higher proportion of polio seroconversions than the <3 group (95% vs. 58%, respectively, p<0.01). Analysis of the <3 subgroup that excluded Tdap vs. the >4 subgroup that excluded Tdap showed no difference between them (p>0.1). However, the >4 subgroup that included Tdap had significantly more seroconversions than either the <3 subgroup that excluded Tdap or the >4 subgroup that excluded Tdap (p<0.01). Overall, at least 98% of subjects were at or above the putative level of seroprotection both pre- and post-vaccination, yet at least 81% of subjects seroconverted. In an analysis of 400 of the subjects in which clinic in- and outpatient encounters were counted over the course of 1 year following vaccinations, there was no significant difference between the 2 groups (p>0.1).
  
  
  CONCLUSIONS
  A combination of >4 vaccines including IPV appeared to have an immunopotentiation effect on polio seroconversion, and Tdap in particular was a strong candidate for an important role. The dose of IPV we studied in our subjects, who already had a high level of seroprotection, acted as a booster. In addition, there appear to be no negative health consequences from receiving few versus more multiple simultaneous vaccinations.
authors.affiliation: Operational Infectious Diseases Department, Naval Health Research Center, McClelland & Patterson Roads, Gate 4 / Bldg 315, San Diego, CA 92106 USA. Electronic address: michael.broderick@med.navy.mil.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Broderick
authors.affiliation: PPLB/DVD/NCIRD Centers for Disease Control and Prevention, 1600 Clifton Road NE, Mailstop G-17, Atlanta, GA 30333 USA.
authors.forename: M Steven
authors.initials: MS
authors.lastname: Oberste
authors.affiliation: PPLB/DVD/NCIRD Centers for Disease Control and Prevention, 1600 Clifton Road NE, Mailstop G-17, Atlanta, GA 30333 USA.
authors.forename: Deborah
authors.initials: D
authors.lastname: Moore
authors.affiliation: PPLB/DVD/NCIRD Centers for Disease Control and Prevention, 1600 Clifton Road NE, Mailstop G-17, Atlanta, GA 30333 USA.
authors.forename: Sandra
authors.initials: S
authors.lastname: Romero-Steiner
authors.affiliation: Operational Infectious Diseases Department, Naval Health Research Center, McClelland & Patterson Roads, Gate 4 / Bldg 315, San Diego, CA 92106 USA.
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Hansen
authors.affiliation: Operational Infectious Diseases Department, Naval Health Research Center, McClelland & Patterson Roads, Gate 4 / Bldg 315, San Diego, CA 92106 USA.
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Faix
mesh_terms: D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood*; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage* / Q000276:immunology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007117:Immunization, Secondary; D008297:Male; D011051:Poliomyelitis / Q000276:immunology*; D017955:Poliovirus / Q000276:immunology*; D011054:Poliovirus Vaccine, Inactivated / Q000008:administration & dosage* / Q000276:immunology; D012189:Retrospective Studies; D000069078:Seroconversion; D014611:Vaccination / Q000009:adverse effects / Q000379:methods; D017778:Vaccines, Combined / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D011054:Poliovirus Vaccine, Inactivated; D017778:Vaccines, Combined
keywords: IPV; Multiple vaccinations; Polio vaccine; Simultaneous vaccination; Td; Tdap