RESUMO
The COVID-19 pandemic has revealed a crucial need for rapid, straightforward collection and testing of biological samples. Serological antibody assays can analyse patient blood samples to confirm immune response following mRNA vaccine administration or to verify past exposure to the SARS-CoV-2 virus. While blood tests provide vital information for clinical analysis and epidemiology, sample collection is not uncomplicated. This process requires a visit to the doctors office, a professionally trained phlebotomist to draw several millilitres of blood, processing to yield plasma or serum, and necessitates appropriate cold chain storage to preserve the specimen. The Covaris truCOLLECT Whole Blood Collection Kit allows for a lancet-based, decentralised capillary blood collection of exactly metered low volumes and eliminates the need for refrigerated transport and storage through the process of active desiccation. Anti-SARS CoV-2 spike and nucleocapsid protein antibody titres in plasma samples collected via venepuncture were compared to antibody titres in whole blood extracts obtained by treating desiccated whole blood samples stored in truCOLLECT sampling devices with Covaris Adaptive-focused Acoustics (AFA). Pearson correlation coefficients of 0.98, 95% CI [0.96, 0.99] for anti-SARS-CoV spike protein antibodies and 0.97, 95% CI [0.94, 0.99] for anti-SARS-CoV-2 nucleocapsid protein antibodies were observed. These data suggest that serology testing using desiccated whole blood samples collected and stored in truCOLLECT devices can be a convenient and cost-effective alternative to conventionally collected plasma.
RESUMO
Among several COVID vaccines that have been approved, the Moderna and Pfizer-BioNTech vaccines are mRNA vaccines that are safe and highly effective at preventing COVID-19 illness. Studies have demonstrated that neutralizing antibody responses elicited by these vaccines correlate strongly with antibodies measured by immunoassays such as ELISA. To monitor the antibody level duration of vaccine-induced immune responses in vaccinated population, cost-effective and easily implementable antibody testing methodologies are urgently needed. In this study, we evaluated the feasibility of using a single drop of fingerstick blood collected with flocked swabs for a high-throughput and quantitative anti-SARS-CoV-2 spike (S1) IgG antibody immunoassay. A total of 50 voluntary subjects participated and donated fingerstick blood samples before and after receiving the Moderna mRNA vaccine. Among all individuals tested, no anti-SARS-CoV-2 S1 IgG antibody was detected before vaccination and on day 7 after receiving the first vaccine dose. On day 14 after the first dose, a significant amount of anti-SARS-CoV-2 S1 IgG antibody was detected in all participants samples. By the end the third week from the first dose, the median anti-SARS-CoV-2 S1 IgG concentration increased to 44.9 ug/mL. No anti-SARS-CoV-2 nucleocapsid (N) protein IgG antibody was detected in any of the participants during the study period, indicating that the anti-SARS-CoV-2 S1 IgG assay is specific for the mRNA vaccine induced antibodies.Comaprison of venous blood plasma and fingerstick blood for anti-SARS-CoV-2 S1 IgG shown a higher correlation. Furthermore, the fingerstick blood dried swab samples are stable for at least 4 days. In summary, we demonstrated that a single drop of fingerstick blood collected with flocked swab can be used for quantitative detection and monitoring of anti-SARS-CoV-2 spike IgG responses after receiving COVID-19 vaccination. This testing platform does not require venous blood draw and can be easily implemented for large scale antibody testing in vaccinated populations.
