Dynamic changes in production of antibodies against SARS-CoV-2 based on three serological kits

ABSTRACT

We wished to understand the dynamic changes in production of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibodies in sera collected from coronavirus disease 19 (COVID-19) patients. Fifty-eight serum samples from 33 patients confirmed to have COVID-19 in Gansu Province, China, were tested for three types of SARS-CoV-2-specific antibodies immunoglobulin (Ig) M, IgG, and total antibodies. The positive rate of IgM, IgG and total antibodies increased gradually with COVID-19 progression. Within the first 3 days, the positive rate of detection of SARS-CoV-2-specific antibody using the three kits was 13.6%-31.8%. whereas, within 4-7 days, it was 36.4%-45.5%, within 8-14 days it was 55.6%-77.8%, and after 15 days, it was 100%. In addition, the three kits were used to measure antibodies from serum samples collected from healthy people, and the specificity was 99%-100%. Statistical analyses indicated no significant difference among the results of the three kits (P > 0.05 for all). In summary, the three SARS-CoV-2 antibody-detection kits had good sensitivity and specificity for detection of antibodies against SARS-CoV-2, and could aid the clinical diagnosis of COVID-19. The dynamic characteristics of production of SARS-CoV-2- specific antibodies could provide important scientific bases for epidemiologic investigations.