Seroprevalence of antibody to varicella among Somali refugees

OBJECTIVES: To determine the seroprevalence of varicella antibody among recent Somali refugees living in Olmsted County, Minnesota, and to estimate the risk of varicella-zoster virus (VZV) infection in this group. SUBJECTS AND METHODS: We obtained blood samples from the study subjects, along with demographic information, immunization records, and vaccine-preventable disease history. Serum samples were tested using a whole-virus IgG VZV-specific commercial enzyme-linked immunosorbent assay kit. This study was completed in 1998. RESULTS: Overall, 200 Somali refugees, comprising 33 extended families, were interviewed, with 193 providing adequate blood samples. Thirty-five subjects (18%) were seronegative for varicella. Males had a significantly higher seronegativity rate (25% [n=23]) compared with females (12% [n=12]; P=.02); however, this association disappeared after adjustment for age and varicella infection history. Five percent (5/92) of adults were seronegative compared with 30% (30/101) of all children (P<.001). Eight percent (5/61) of the adult females were seronegative, whereas none (0/31) of the adult males were seronegative. Conversely, 38% (23/60) of male children were seronegative compared with 17% (7/41) of female children (P<.001). CONCLUSION: These results demonstrate a high prevalence of varicella seronegativity among Somali refugees who have immigrated to an endemic area. We recommend instituting improved education regarding varicella among Somali communities and increasing vaccine uptake or routine testing for serum varicella antibody to prevent VZV-related morbidity and mortality, particularly in adolescents, adult refugees, and women of childbearing age.