Population-Level Persistence of Immunity 2 Years After the PsA-TT Mass-Vaccination Campaign in Mali.
Clin Infect Dis
; 61 Suppl 5: S547-53, 2015 Nov 15.
Article
em En
| MEDLINE
| ID: mdl-26553687
ABSTRACT
BACKGROUND:
In 2010, Africa's first preventive meningococcal mass vaccination campaign was launched using a newly developed Neisseria meningitidis group A (NmA) polysaccharide-tetanus toxoid conjugate vaccine, PsA-TT (MenAfriVac), designed specifically for the meningitis belt. Given PsA-TT's recent introduction, the duration of protection against meningococcal group A is unknown.METHODS:
We conducted a household-based, age-stratified seroprevalence survey in Bamako, Mali, in 2012, 2 years after the vaccination campaign targeted all 1- to 29-year-olds. Randomly selected participants who had been eligible for PsA-TT provided a blood sample and responded to a questionnaire. Sera were analyzed to assess NmA-specific serum bactericidal antibody titers using rabbit complement (rSBA) and NmA-specific immunoglobulin G (IgG) by enzyme-linked immunosorbent assay. The proportion of participants putatively protected and the age group- and sex-specific rSBA geometric mean titers (GMTs) and IgG geometric mean concentrations (GMCs) were determined.RESULTS:
Two years postvaccination, nearly all of the 800 participants (99.0%; 95% confidence interval [CI], 98.3%-99.7%) maintained NmA-specific rSBA titers ≥8, the accepted threshold for protection; 98.6% (95% CI, 97.8%-99.4%) had titers ≥128, and 89.5% (95% CI, 87.4%-91.6%) had titers ≥1024. The rSBA GMTs were significantly higher in females than in males aged <18 years at vaccination (P < .0001). NmA-specific IgG levels ≥2 µg/mL were found in 88.5% (95% CI, 86.3%-90.7%) of participants.CONCLUSIONS:
Two years after PsA-TT introduction, a very high proportion of the population targeted for vaccination maintains high antibody titers against NmA. Assessing the duration of protection provided by PsA-TT is a priority for implementing evidence-based vaccination strategies. Representative, population-based seroprevalence studies complement clinical trials and provide this key evidence.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Vacinas Meningocócicas
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Neisseria meningitidis Sorogrupo A
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Meningite Meningocócica
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Anticorpos Antibacterianos
Limite:
Adolescent
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Adult
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Animals
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Child
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Child, preschool
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Female
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Humans
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Infant
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Male
País/Região como assunto:
Africa
Idioma:
En
Revista:
Clin Infect Dis
Assunto da revista:
DOENCAS TRANSMISSIVEIS
Ano de publicação:
2015
Tipo de documento:
Article