Revaccination with locally-produced vi typhoid polysaccharide vaccine among chinese school-aged children: safety and immunogenicity findings.
Pediatr Infect Dis J
; 26(11): 1001-5, 2007 Nov.
Article
em En
| MEDLINE
| ID: mdl-17984806
ABSTRACT
OBJECTIVE:
To evaluate the safety and immunogenicity of revaccination with locally-produced Vi polysaccharide vaccine 3 years after the first dose in Chinese children aged 9 to 14 years.METHODS:
A randomized, placebo-controlled trial was conducted in Suzhou, Jiangsu, China. Six hundred and sixty-seven eligible children who had previously received a primary dose of Vi vaccine were randomly assigned to receive 1 dose of 30 mug Vi vaccine or placebo. In addition, 331 eligible children received 1 dose of Vi polysaccharide vaccine as a primary vaccination. Adverse events were followed for 28 days after vaccination. Serum samples were collected from a subgroup of participants on day 0 and day 28, and Vi antibodies were analyzed using a passive hemagglutination method.RESULTS:
Revaccination was found to be safe and immunogenic. No severe adverse events were observed. A significant increase in antibody titers after vaccination was observed among children who had and had not been previously vaccinated. Twenty-eight days after injection, the seropositive rate was 79% in both revaccination and primary injection groups; the geometric mean antibody titer was 140 in the primary injection group and 129 in the revaccination group (P = 0.24). Although the difference of attained geometric mean titers in follow-up sera was not significantly different in these 2 groups, the fold-rise of these titers from baseline was significantly higher in the primary injection group than in the revaccination group (7.7 versus 3.1, P < 0.001).CONCLUSION:
We found that revaccination using the locally produced Vi polysaccharide vaccine among Chinese school-aged children was safe and increased antibody titers. Revaccination can be used to extend the duration of protection provided by Vi polysaccharide vaccine.
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Base de dados:
MEDLINE
Assunto principal:
Polissacarídeos Bacterianos
/
Febre Tifoide
/
Vacinas Tíficas-Paratíficas
/
Imunização Secundária
/
Anticorpos Antibacterianos
Tipo de estudo:
Clinical_trials
/
Diagnostic_studies
Limite:
Adolescent
/
Child
/
Female
/
Humans
/
Male
País/Região como assunto:
Asia
Idioma:
En
Revista:
Pediatr Infect Dis J
Assunto da revista:
DOENCAS TRANSMISSIVEIS
/
PEDIATRIA
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
China