It is estimated that over 250,000 babies are born with sickle cell disease (SCD) annually in sub-Saharan Africa, and only 10% - 50% of them survive beyond five years of age. Data describing the magnitude of the sickle cell problem are lacking in most African countries. The available data on prevalence were mainly from older studies and small numbers of hospitalized patients. In Uganda, approximately 25,000 children are born with SCD but 70-80% die before their 5th birthday. Lehmann and Raper found 'sicklaemia' prevalence of 0.8% and 45% in the Sebei and Bambaa ethnic groups, respectively. A recent study found a SCT and SCD prevalence of 3% - 19% and 0% - 3%, respectively but this study addressed only 5 of Uganda's 111 districts and used a small convenience sample of children aged 6 - 60 months. The objective of this study is to determine the prevalence and map out the burden of SCT and SCD in Uganda.

The investigators propose a cross-sectional study of sickle cell trait (SCT) and disease in all districts of Uganda using dried blood spots (DBS) collected from HIV exposed babies over a 12-month period. About 90,000 DBS samples collected from HIV exposed children from all districts of Uganda from February 2014 to March 2015 will be analyzed. Follow-up analysis will occur on up to 1,000,000 samples collected during 2015 - 2030 based on surveillance findings and secondary objectives. The study will be conducted at the Central Public Health (CPHL) in Kampala where the samples from across the country are collected for PCR testing. The investigators will perform hemoglobin analysis using isoelectric focusing (IEF). The overall prevalence and the prevalence by district of SCT and SCD will be determined. Geospatial mapping will be performed using a specialized software program to produce a map illustrating the prevalence of SCT and SCD throughout the country and allow associations between sickle cell trait/disease with either malaria prevalence or HIV co-morbidity. Further analysis of sickle cell disease or hemoglobin variants will be conducted using HPLC and DNA-based techniques.

Inclusion Criteria:

• Up to 1,000,000 samples may be collected during 2015 - 2030 following primary analysis based on surveillance findings.

Exclusion Criteria:

• Repeat samples on the same individuals during the study period will be excluded.

All Dried Blood Spot (DBS) samples collected from HIV exposed infants from all districts of Uganda from approximately February 2014 to March 2015 will be included in the primary analysis. Up to 1,000,000 additional samples may be collected during 2015 - 2030 following primary analysis based on surveillance findings.