Determination of varicella immunity by the indirect immunofluorescence test in urgent clinical situations.

Certain categories of patients run an increased medical risk when exposed to varicella. Newborns lacking maternal immunity, immunosuppressed leukemic children or children with other immunodeficient disorders may gain a decisive benefit by administration of e.g. interferon or of specific immunoglobulin against varicella. An indirect immunofluorescence (IF) method has been used to estimate varicella. An indirect immunofluorescence (IF) method has been used to estimate varicella immunity. Of 51 heavily exposed women denying earlier varicella, 39 were found to be immune by the test and none of those contracted varicella, whereas 9 out of the 12 non-immune women fell ill. 14/48 immunosuppressed children were found to be seropositive and none of these contracted varicella, whereas 13 mild or subclinical cases occurred among the 34 seronegative children. The same test revealed that 175/182 (96%) young adults in Sweden were immune. The indirect IF test is considered a rapid, simple and reliable method for estimating varicella immunity.