Blood and saliva SARS-CoV-2 antibody levels in self-collected dried spot samples

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Medical Microbiology and Immunology, Volume 211, issue 4
We examined the usefulness of dried spot blood and saliva samples in SARS-CoV-2 antibody analyses. We analyzed 1231 self-collected dried spot blood and saliva samples from healthcare workers. Participants filled in a questionnaire on their COVID-19 exposures, infections, and vaccinations. Anti-SARS-CoV-2 IgG, IgA, and IgM levels were determined from both samples using the GSP/DELFIA method. The level of exposure was the strongest determinant of all blood antibody classes and saliva IgG, increasing as follows: (1) no exposure (healthy, non-vaccinated), (2) exposed, (3) former COVID-19 infection, (4) one vaccination, (5) two vaccinations, and (6) vaccination and former infection. While the blood IgG assay had a 99.5% sensitivity and 75.3% specificity to distinguish participants with two vaccinations from all other types of exposure, the corresponding percentages for saliva IgG were 85.3% and 65.7%. Both blood and saliva IgG-seropositivity proportions followed similar trends to the exposures reported in the questionnaires. Self-collected dry blood and saliva spot samples combined with the GSP/DELFIA technique comprise a valuable tool to investigate an individual’s immune response to SARS-CoV-2 exposure or vaccination. Saliva IgG has high potential to monitor vaccination response wane, since the sample is non-invasive and easy to collect.
Funding Information: Open Access funding provided by University of Helsinki. The study has been supported by The Finnish Dental Society Apollonia (grant for MP and LL), the Helsinki and Uusimaa Hospital District (HUS, grant for LL). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The data of this study has not been presented elsewhere. Publisher Copyright: © 2022, The Author(s).
Antibody, Blood, COVID-19, Dried spot sample, Exposure, Saliva, SARS-CoV-2, Vaccination
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Lahdentausta , L , Kivimäki , A , Oksanen , L , Tallgren , M , Oksanen , S , Sanmark , E , Salminen , A , Geneid , A , Sairanen , M , Paju , S , Saksela , K , Pussinen , P & Pietiäinen , M 2022 , ' Blood and saliva SARS-CoV-2 antibody levels in self-collected dried spot samples ' , Medical Microbiology and Immunology , vol. 211 , no. 4 , pp. 173-183 .