The course of Varicella appears to be more aggressive in immunocompromised hosts. In a recent series on human immunodeficiency virus-infected patients from South Africa, seven of 12 patients who were hospitalised with chickenpox developed clinically severe pneumonia and, despite receiving antiviral within 12 h of admission, three (43%) died
21. A review of 38 cases of adult renal allograft recipients with disseminated Varicella infection, reported in 15 different studies, found that of the 29 patients with primary Varicella, 29% developed Varicella pneumonia and the overall mortality was 34%. However, the mortality from 1981–1990 was 53% and from 1990–2000 was 22%
23. The improvement in mortality rate was most likely to have been influenced by the availability of specific antiviral therapy, since antiviral therapy was used in 33% of cases before 1990 and 74% of cases after 1990.