Implementation of Cryptococcal Antigenemia Screen and Treat Programs to prevent Meningitis in Persons Living with HIV Infection

Introduction: The fungus Cryptococcus neoformans causes life-threatening meningitis in hundreds of thousands of people with weakened immune systems every year. Cryptococcus is the most common cause of meningitis in sub-Saharan Africa, and is a leading cause of death among people with HIV infection. A simple, affordable blood test for cryptococcal antigen (CrAg) can detect cryptococcal infection before meningitis develops, creating an opportunity to prevent this deadly disease. Additionally, this approach can help prevent immune reconstitution inflammatory syndrome (IRIS) in patients with low CD4 counts in whom antiretroviral therapy is initiated, by reducing the risk of unmasking asymptomatic cryptococcal infection.

Methods: CDC collaborates with governmental, non-governmental, private and academic partners to coordinate, implement and develop policy guidance for targeted cryptococcal screening programs. These programs seek to reduce Cryptococcus-related mortality while building laboratory capacity to detect early infection and easing the costly burden to the healthcare system of hospitalization and treatment for cryptococcal meningitis. To achieve these goals, health centers and laboratories are beginning to routinely screen HIV-positive patients presenting with a CD4 count below a certain threshold (e.g. <100 cells/mm³). CrAg-positive patients are treated according to a clinical algorithm involving assessment for symptoms of meningitis, treatment with anti-fungal medication and delay of ART initiation to IRIS.

Results: To date, CDC has assisted with the planning and piloting of CrAg screening and treatment programs in 12 countries, mostly in sub-Saharan Africa. Of these countries, eight have incorporated screening into national HIV treatment guidelines and are moving towards implementing programs nationally. In South Africa, over 27,000 patients have been screened during the pilot phase of national implementation; the pilot has so far identified over 1,000 CrAg-positive patients, in >60% of whom preemptive antifungal treatment was  successfully started.

Conclusion: Cryptococcal screening and treatment programs offer a relatively inexpensive and easily implemented method of reducing mortality amongst AIDS patients. As countries incorporate screening into guidelines, lessons learned from the implementation in recent years around the globe can inform these future efforts to better detect the disease early and reduce mortality.