Abstract
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.
Keywords: Antibody; Blood; COVID-19; Dried spot sample; Exposure; SARS-CoV-2; Saliva; Vaccination.
【저자키워드】 COVID-19, SARS-CoV-2, Saliva, vaccination, antibody, Blood, exposure, Dried spot sample, 【초록키워드】 IgG, IgM, immune response, vaccination, Infection, sensitivity, specificity, infections, SARS-CoV-2 antibody, COVID-19 infection, IgA, healthcare, questionnaire, Vaccinations, Questionnaires, Non-invasive, participant, while, MONITOR, analyzed, examined, proportion, healthy, reported, analyses, percentage, 【제목키워드】 SARS-CoV-2 antibody,