[Safety and efficacy of varicella vaccine in healthy children--one year follow-up].
OBJECTIVE
to assess the safety and efficacy of varicella virus vaccine after administration of one dose.


METHODS
106 healthy children (59 girls, 47 boys), with no history of varicella, were vaccinated between March and April 2004. The subjects were aged 9 months to 12 years (median 47 months). Antibody concentrations were determined twice: after 46 days (test 1) and after 13 months (test 2). The concentration of IgG-antibody against VZV was measured using the ELISA IgG Test kit (Genzyme Virotech, Germany).


RESULTS
no local and/or general symptoms were observed after vaccination. Effectiveness of vaccination was 98.1%. Two vaccinated children with borderline values (antibody concentrations were 9-11 VE) developed a mild form of varicella 13 months after vaccination. Protective levels of antibody concentrations were found in 95 out of 106 children (89.6%) 46 days after vaccination and in 72 out of 104 children (69.2%) 13 months after vaccination. The mean antibody concentration 46 days after vaccination (test 1) was 21.3VE (6.7-43.8 VE), and 13 months after vaccination (test 2) was 17.2VE (4.9-38.4) i.e. significantly lower (p<0.001). In both tests no significant statistical differences were noted between the post-vaccination concentrations in girls (VE1-20.6 and VE2-22.2) and boys ( VE2-17.3 and VE2-17.0). Neither the subjects' age nor sex at the time of vaccination correlated with the decreased antibody concentrations 13 months after vaccination. In 27.4% of children statistically significant lowering of antibody concentration was detected 13 months after vaccination (lp < 0.0001).


CONCLUSIONS
the varicella vaccine (Varilrix) was found to be safe and its effectiveness was 98.1% after 13 months. Only in 2 children mild clinical sings of varicella occurred. However, because of a statistically significant lowering of antibody concentration 13 months after the vaccination, a two dose regimen of varicella vaccination should be recommended.
Klinika Pediatrii Centrum Medycznego Kształcenia Podyplomowego w Warszawie. tjackowska@cmkp.edu.pl
Teresa
T
Jackowska
January
J
Dziadek
Robert
R
Wasilewski
Maria
M
Wasik
D000914:Antibodies, Viral / Q000032:analysis; D000917:Antibody Formation; D002644:Chickenpox / Q000517:prevention & control*; D019433:Chickenpox Vaccine / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007115:Immunization Schedule; D007074:Immunoglobulin G / Q000032:analysis; D007223:Infant; D007231:Infant, Newborn; D008297:Male
D000914:Antibodies, Viral; D019433:Chickenpox Vaccine; D007074:Immunoglobulin G