Evaluation of SARS-CoV-2 antibody response between paired fingerprick (hemaPEN) and venepuncture collected samples in children and adults

Serological surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies is important to monitor population COVID-19 immunity. Dried blood spots (DBS) are a valuable method for serosurveys, particularly in remote settings and in children. We compared the measurement of SARS-CoV-2 spike-specific IgG in paired blood samples collected by standard venepuncture (serum) and the hemaPEN microsampling DBS device from children and adults using an established in-house ELISA. A total of 83 participants (10 months to 65 years of age) with paired serum and hemapen samples were included in the analysis; N=41 adults (36 COVID-positive and 5 COVID-negative) and N=42 children (37 COVID positive and 5 COVID-negative). Moderate- to strong-correlations between paired hemaPEN DBS eluates and serum SARS-CoV-2 IgG antibodies for RBD (r=0.9472, P<.0001) and S1 proteins (r=0.6892, P<.0001) were found. Similar results were observed in both adult and paediatric populations. SARS-CoV-2 spike-specific IgG in hemaPEN DBS samples remained stable for at least 35 weeks at room temperature. HemaPEN samples showed high specificity and sensitivity (100% and 89.89%, respectively) compared with serum. The use of the microsampling hemaPEN device for DBS sample collection is a feasible approach for assessing SARS-CoV-2 antibodies for serosurveillance studies, particularly in remote settings and in children.