Prevalence of Cryptococcal Antigenemia and Cost-Effectiveness of a Cryptococcal Antigen Screening Program – Vietnam

BACKGROUND An estimated 120,000 HIV-associated cryptococcal meningitis (CM) cases occur each year in South and Southeast Asia; early treatment may improve outcomes. The World Health Organization (WHO) recently recommended screening HIV-infected adults with CD4<100 cells/mm(3) for serum cryptococcal antigen (CrAg), a marker of early cryptococcal infection, in areas of high CrAg prevalence. We evaluated CrAg prevalence and cost-effectiveness of this screening strategy in HIV-infected adults in northern and southern Vietnam. METHODS Serum samples were collected and stored during 2009-2012 in Hanoi and Ho Chi Minh City, Vietnam, from HIV-infected, ART-naïve patients presenting to care in 12 clinics. All specimens from patients with CD4<100 cells/mm(3) were tested using the CrAg lateral flow assay. We obtained cost estimates from laboratory staff, clinicians and hospital administrators in Vietnam, and evaluated cost-effectiveness using WHO guidelines. RESULTS Sera from 226 patients [104 (46%) from North Vietnam and 122 (54%) from the South] with CD4<100 cells/mm(3) were available for CrAg testing. Median CD4 count was 40 (range 0-99) cells/mm(3). Nine (4%; 95% CI 2-7%) specimens were CrAg-positive. CrAg prevalence was higher in South Vietnam (6%; 95% CI 3-11%) than in North Vietnam (2%; 95% CI 0-6%) (p = 0.18). Cost per life-year gained under a screening scenario was $190, $137, and $119 at CrAg prevalences of 2%, 4% and 6%, respectively. CONCLUSION CrAg prevalence was higher in southern compared with northern Vietnam; however, CrAg screening would be considered cost-effective by WHO criteria in both regions. Public health officials in Vietnam should consider adding cryptococcal screening to existing national guidelines for HIV/AIDS care.