Estimated Prevalence of <i>Cryptococcus</i> Antigenemia (CrAg) among HIV-Infected Adults with Advanced Immunosuppression in Namibia Justifies Routine Screening and Preemptive Treatment

<div><p>Background</p><p>Cryptococcal meningitis is common and associated with high mortality among HIV infected persons. The World Health Organization recommends that routine Cryptococcal antigen (CrAg) screening in ART-naïve adults with a CD4⁺ count <100 cells/μL followed by pre-emptive antifungal therapy for CrAg-positive patients be considered where CrAg prevalence is ≥3%. The prevalence of CrAg among HIV adults in Namibia is unknown. We estimated CrAg prevalence among HIV-infected adults receiving care in Namibia for the purpose of informing routine screening strategies.</p><p>Methods</p><p>The study design was cross-sectional. De-identified plasma specimens collected for routine CD4⁺ testing from HIV-infected adults enrolled in HIV care at 181 public health facilities from November 2013 to January 2014 were identified at the national reference laboratory. Remnant plasma from specimens with CD4⁺ counts <200 cells/μL were sampled and tested for CrAg using the IMMY^® Lateral Flow Assay. CrAg prevalence was estimated and assessed for associations with age, sex, and CD4⁺ count.</p><p>Results</p><p>A total of 825 specimens were tested for CrAg. The median (IQR) age of patients from whom specimens were collected was 38 (32–46) years, 45.9% were female and 62.9% of the specimens had CD4 <100 cells/μL. CrAg prevalence was 3.3% overall and 3.9% and 2.3% among samples with CD4⁺ counts of CD4⁺<100 cells/μL and 100–200 cells/μL, respectively. CrAg positivity was significantly higher among patients with CD4+ cells/μL < 50 (7.2%, P = 0.001) relative to those with CD4 cells/μL 50–200 (2.2%).</p><p>Conclusion</p><p>This is the first study to estimate CrAg prevalence among HIV-infected patients in Namibia. CrAg prevalence of ≥3.0% among patients with CD4⁺<100 cells/μL justifies routine CrAg screening and preemptive treatment among HIV-infected in Namibia in line with WHO recommendations. Patients with CD4⁺<100 cells/μL have a significantly greater risk for CrAg positivity. Revised guidelines for ART in Namibia now recommend routine screening for CrAg.</p></div

Prevalence and correlates of CrAg positivity among HIV-infected adults with advanced immunosuppression in Namibia, 2013–14.

<p>Prevalence and correlates of CrAg positivity among HIV-infected adults with advanced immunosuppression in Namibia, 2013–14.</p

Select demographic and clinical characteristics of sampled patients, sero-survey of <i>Cryptococcus</i> antigenemia among HIV-infected adults with advanced immunosuppression in Namibia, 2013–14.

<p>Select demographic and clinical characteristics of sampled patients, sero-survey of <i>Cryptococcus</i> antigenemia among HIV-infected adults with advanced immunosuppression in Namibia, 2013–14.</p