title: Higher Tetanus Toxoid Immunity 2 Years After PsA-TT Introduction in Mali.
abstract: BACKGROUND
  In 2010, mass vaccination with a then-new meningococcal A polysaccharide-tetanus toxoid protein conjugate vaccine (PsA-TT, or MenAfriVac) was undertaken in 1- to 29-year-olds in Bamako, Mali. Whether vaccination with PsA-TT effectively boosts tetanus immunity in a population with heterogeneous baseline tetanus immunity is not known. We assessed the impact of PsA-TT on tetanus toxoid (TT) immunity by quantifying age- and sex-specific immunity prior to and 2 years after introduction.
  
  
  METHODS
  Using a household-based, age-stratified design, we randomly selected participants for a prevaccination serological survey in 2010 and a postvaccination survey in 2012. TT immunoglobulin G (IgG) antibodies were quantified and geometric mean concentrations (GMCs) pre- and postvaccination among all age groups targeted for vaccination were compared. The probability of TT IgG levels ≥0.1 IU/mL (indicating short-term protection) and ≥1.0 IU/mL (indicating long-term protection) by age and sex was determined using logistic regression models.
  
  
  RESULTS
  Analysis of 793 prevaccination and 800 postvaccination sera indicated that while GMCs were low pre-PsA-TT, significantly higher GMCs in all age-sex strata were observed 2 years after PsA-TT introduction. The percentage with short-term immunity increased from 57.1% to 88.4% (31.3-point increase; 95% confidence interval [CI], 26.6-36.0;, P < .0001) and with long-term immunity increased from 20.0% to 58.5% (38.5-point increase; 95% CI, 33.7-43.3; P < .0001) pre- and postvaccination.
  
  
  CONCLUSIONS
  Significantly higher TT immunity was observed among vaccine-targeted age groups up to 2 years after Mali's PsA-TT mass vaccination campaign. Our results, combined with evidence from clinical trials, strongly suggest that conjugate vaccines containing TT such as PsA-TT should be considered bivalent vaccines because of their ability to boost tetanus immunity.
authors.affiliation: Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis Fogarty International Center, National Institutes of Health, Bethesda, Maryland.
authors.forename: Nicole E
authors.initials: NE
authors.lastname: Basta
authors.affiliation: Vaccine Evaluation Unit, Public Health England, Manchester Royal Infirmary, United Kingdom.
authors.forename: Ray
authors.initials: R
authors.lastname: Borrow
authors.affiliation: Centre pour le Développement des Vaccins, Ministère de la Santé, Bamako, Mali.
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Berthe
authors.affiliation: Centre pour le Développement des Vaccins, Ministère de la Santé, Bamako, Mali.
authors.forename: Uma
authors.initials: U
authors.lastname: Onwuchekwa
authors.affiliation: Centre pour le Développement des Vaccins, Ministère de la Santé, Bamako, Mali.
authors.forename: Awa Traoré Eps
authors.initials: AT
authors.lastname: Dembélé
authors.affiliation: Vaccine Evaluation Unit, Public Health England, Manchester Royal Infirmary, United Kingdom.
authors.forename: Rachael
authors.initials: R
authors.lastname: Almond
authors.affiliation: Vaccine Evaluation Unit, Public Health England, Manchester Royal Infirmary, United Kingdom.
authors.forename: Sarah
authors.initials: S
authors.lastname: Frankland
authors.affiliation: Vaccine Evaluation Unit, Public Health England, Manchester Royal Infirmary, United Kingdom.
authors.forename: Sima
authors.initials: S
authors.lastname: Patel
authors.affiliation: Vaccine Evaluation Unit, Public Health England, Manchester Royal Infirmary, United Kingdom.
authors.forename: Daniel
authors.initials: D
authors.lastname: Wood
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom.
authors.forename: Maria
authors.initials: M
authors.lastname: Nascimento
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom Medical Research Council Unit, Fajara, The Gambia.
authors.forename: Olivier
authors.initials: O
authors.lastname: Manigart
authors.affiliation: Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, United Kingdom.
authors.forename: Caroline L
authors.initials: CL
authors.lastname: Trotter
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom.
authors.forename: Brian
authors.initials: B
authors.lastname: Greenwood
authors.affiliation: Centre pour le Développement des Vaccins, Ministère de la Santé, Bamako, Mali.
authors.forename: Samba O
authors.initials: SO
authors.lastname: Sow
mesh_terms: D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008302:Mali; D022401:Meningococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D013743:Tetanus Antitoxin / Q000097:blood*; D013745:Tetanus Toxoid / Q000276:immunology*; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; C573970:MenAfriVac; D022401:Meningococcal Vaccines; D013743:Tetanus Antitoxin; D013745:Tetanus Toxoid
keywords: Africa; conjugate; meningococcal vaccines; seroprevalence; tetanus