Brief Report: Safety of Frequent Blood Sampling in Research Participants in an Acute HIV Infection Cohort in Thailand

INTRODUCTION: Anemia is a potential adverse effect of phlebotomy during participation in research. Clinical studies of acute HIV infection (AHI) require frequent phlebotomy to maximize scientific yield, but this participant population may also be at increased risk for anemia and other adverse events. OBJECTIVE: The objective of this study was to describe baseline and longitudinal hemoglobin changes among participants with AHI. METHODS: Participants with AHI (n = 202) were enrolled in a prospective cohort study in Thailand. AHI was diagnosed using pooled nucleic acid testing and sequential HIV antibody immunoassays. Antiretroviral therapy was initiated on enrollment. During 48 weeks of study participation, a total of 629 mL of blood was drawn over 14 visits. Hemoglobin levels were measured serially, and abnormalities were graded using the Division of AIDS (National Institute of Allergy and Infectious Diseases) adverse event table. RESULTS: AHI was diagnosed at a median of 18 days after infection. Mean hemoglobin at enrollment of male participants was 14.8 g/dL, and for females, it was 13.0 g/dL. Over 48 weeks, there was a mean increase of 0.2 g/dL among men (P = 0.01) and a decrease of 0.7 g/dL among women (P = 0.03). The overall prevalence of anemia was low, with 7 (3.5%) of 202 fulfilling grade 1 or 2 anemia criteria. CONCLUSIONS: Anemia was rare after frequent phlebotomy in research participants with AHI, before and after antiretroviral therapy. Given that the blood volume drawn from this study did not pose substantial clinical risk, increasing the volume of blood drawn for research purposes in acute HIV-infected research participants could be considered for future studies.