Short Report: Hepatitis B Infection and Severe Plasmodium Falciparum Malaria in Vietnamese Adults

We investigated the prevalence of infection with hepatitis B virus among adult Vietnamese patients hospitalized for severe Plasmodium falciparum malaria. Sera from patients admitted with severe malaria in Ho Chi Minh City, Vietnam, between May 1991 and January 1996 were assayed for hepatitis B surface antigen (HBsAg) by a commercial enzyme-linked immunosorbent assay kit. The overall prevalence of HBsAg was 23.77% (77 of 324). This was higher than reported estimates of prevalence in the general catchment population for the study hospital (mean, 9.8%; range, 9-16%). No association was found between risk of death caused by severe malaria and HBsAg. Patients admitted with cerebral malaria had a slightly greater risk of registering positive for HBsAg (relative risk, 1.28; 95% confidence interval, 1.04-1.58) relative to other manifestations of severe malaria. Chronic infection with hepatitis B virus may be a risk factor for severe malaria. Despite remarkable achievements in reducing malaria mor- tality, malaria remains the most common cause of morbidity and mortality in Vietnam. Of the 71.6 million population, 41.9 million are at risk for malaria; 15 million live in malaria- endemic areas. 1 The majority of people with malaria are not admitted to the hospital. Instead, they receive oral therapy on an outpatient basis. People who develop severe malaria and enter the hospital represent a minority of patients. This report examines the association of infection with hepatitis B and severe malaria and the impact of that factor on survival. Hepatitis B, a double-stranded DNA virus of the hepadnoviridae family, infects 15% of people in South- east Asia. 2 Globally, 2 billion people are infected; 350 million of which are asymptomatic carriers of the virus. 3 The infection kills 1 million carriers annually, with mortality generally associated with complications of cirrhosis, hepa- tocellular carcinoma, and, rarely, fulminant liver failure dur- ing acute infection. 4,5 Coendemic falciparum malaria and acute hepatitis B occur through much of Southeast Asia, Africa, and the tropical Americas. Both diseases represent key threats to public health. To our knowledge, large studies evaluating the effect of acute hepatitis B infection on risk of severe disease and death caused by falciparum malaria have not been reported. We hypothesized that acute hepatitis B may exacerbate the risk of sequelae with infection by Plasmodium falciparum. By assaying for hepatitis B surface antigen, a marker for active infection, among patients admitted to hospital in Vi- etnam and enrolled into a treatment trial for severe malaria, we were able to test this hypothesis. 6