This study aims to evaluate the determinants of breakthrough infection after one dose of varicella vaccine. We designed a retrospective case-control study. Breakthrough cases were children, aged 1-15, who presented varicella symptoms ≥ 42 days after the first dose of varicella vaccine (breakthrough). Controls were children, aged 1-15 years, who attended the same class (in a school or in a kindergarten) than the cases in the year of the breakthrough onset; they received a dose of varicella vaccine ≥ 42 days before the case rash onset and they did not develop varicella symptoms. We enrolled 45 cases and 135 controls. 40% of cases (n = 18; 95% CI = 25.4-54. 6) presented at least one risk factor; this proportion was 39.2% (95% CI = 30.9-47.6) among the controls (chi-square = 0.0078; P = 0.93). Time between vaccination and virus exposure was longer among cases. Logistic regression showed that breakthrough disease was associated with duration of time from vaccination.
Determinants of varicella breakthrough: Results of a 2012 case control study
MARTINELLI, DOMENICO;PRATO, ROSA;
2014-01-01
Abstract
This study aims to evaluate the determinants of breakthrough infection after one dose of varicella vaccine. We designed a retrospective case-control study. Breakthrough cases were children, aged 1-15, who presented varicella symptoms ≥ 42 days after the first dose of varicella vaccine (breakthrough). Controls were children, aged 1-15 years, who attended the same class (in a school or in a kindergarten) than the cases in the year of the breakthrough onset; they received a dose of varicella vaccine ≥ 42 days before the case rash onset and they did not develop varicella symptoms. We enrolled 45 cases and 135 controls. 40% of cases (n = 18; 95% CI = 25.4-54. 6) presented at least one risk factor; this proportion was 39.2% (95% CI = 30.9-47.6) among the controls (chi-square = 0.0078; P = 0.93). Time between vaccination and virus exposure was longer among cases. Logistic regression showed that breakthrough disease was associated with duration of time from vaccination.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
