Cost-effectiveness of serotesting vs. presumptive immunization for varicella in new immigrants.
Objective: Assess cost-effectiveness of serotesting vs. presumptive varicella immunization by age and accuracy of history of varicella disease, to develop immunization policy in a refugee clinic.
Methods: We assess seroprevalence of immunity to varicella in refugee children. Banked serum from 508 refugees from former Yugoslavia, East Africa and Vietnam were tested using a rapid ELISA (Diamedix, Miami, FL) We calculate a prevalence critical value above which it is cost-effective to serotest rather than immunize presumptively and compare this with region-specific seroprevalence. Varicella history was ascertained by chart review and compared with serologic result.
Results: Percent varicella antibody by age (95% CI)
Age Former Yugoslavia East Africa Vietnam (N=342) (n=145) (n=42) 1-4 23 (14, 32) 19 (4, 34) 0 5-6 64 (47, 80) 76 (56, 97) 0 7-8 74 (61, 87) 82 (64, 100) 0 9-10 90 (81, 99) 73 (51, 96) 33 (0, 87) 11-14 77 (68, 86) 74 (60, 88) 82 (60,100)
Critical prevalence value for children < 13 (single vaccine dose) was 34%, and for adolescents > 13 (2 doses) was 17%. Serotesting is cost-effective for children > 5 years from former Yugoslavia and East Africa and for children > 11 years from Vietnam. Positive predictive value of history of varicella disease was 95% in children from former Yugoslavia (6 children had positive history and undetectable antibody) and 53% for children from Vietnam.
Conclusion: Immunization policy can be developed based upon knowledge of seroprevalence of varicella and accuracy of historical information about varicella disease.
Learning Objectives: To understand varicella immunization issues in new refugees
Keywords: Refugees, Immunizations
Presenting author's disclosure statement:
Organization/institution whose products or services will be discussed: none
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.