SARS-CoV-2 Specific IgG Antibodies Persist Over a 12-Month Period in Oral Mucosal Fluid Collected From Previously Infected Individuals

Abstract

BackgroundDeveloping an understanding of the antibody response, seroprevalence, and seroconversion from natural infection and vaccination against SARS-CoV-2 will give way to a critical epidemiological tool to predict reinfection rates, identify vulnerable communities, and manage future viral outbreaks. To monitor the antibody response on a larger scale, we need an inexpensive, less invasive, and high throughput method.MethodsHere we investigate the use of oral mucosal fluids from individuals recovered from SARS-CoV-2 infection to monitor antibody response and persistence over a 12-month period. For this cohort study, enzyme-linked immunosorbent assays (ELISAs) were used to quantify anti-Spike(S) protein IgG antibodies in participants who had prior SARS-CoV-2 infection and regularly (every 2-4 weeks) provided both serum and oral fluid mucosal fluid samples for longitudinal antibody titer analysis.ResultsIn our study cohort (n=42) with 17 males and 25 females with an average age of 45.6 +/- 19.3 years, we observed no significant change in oral mucosal fluid IgG levels across the time course of antibody monitoring. In oral mucosal fluids, all the participants who initially had detectable antibodies continued to have detectable antibodies throughout the study.ConclusionsBased on the results presented here, we have shown that oral mucosal fluid-based assays are an effective, less invasive tool for monitoring seroprevalence and seroconversion, which offers an alternative to serum-based assays for understanding the protective ability conferred by the adaptive immune response from viral infection and vaccination against future reinfections.

Differences in systemic and mucosal SARS-CoV-2 antibody prevalence in a prospective cohort of Dutch children

“…Median time since last exposure or vaccination respectively was six-fold longer in the infected group as compared to the vaccinated group which is likely to contribute to this difference. Considering that some studies measure similar durability for serum and mucosal SARS-CoV-2 IgG (38,39), heterogeneity in the response itself could also explain the differences between compartments. If exposure to the virus does not elicit identical humoral immune responses in all individuals, this may explain the lower saliva prevalence reported in several COVID-19 cohorts (18, 40).…”

SARS-CoV-2 reinfections: Overview of efficacy and duration of natural and hybrid immunity

“…Taken together, epidemiological studies indicate that protection against reinfections by natural immunity lasts for over one year with only moderate, if at all, decline over this period. The notion of long-term protection against-reinfections is also underpinned by data on persistance of anti SARS-CoV-2 antibodies and cellular immunity over more than one year in the majority of patients ( Chellamuthu et al, 2021 ; Dehgani-Mobaraki et al, 2021 ; Gussarow et al, 2021 ; Lau et al, 2021 ; Rosati et al, 2021 ).…”

Capillary driven microfluidic sequential flow device for point-of-need ELISA: COVID-19 serology testing

“…The detection limit of CaDI was 2.8 ng/mL, nearly the same as a traditional well-plate ELISA (1.2 ng/mL). Several retrospective studies indicate that the 2.8 ng/ml LOD for antibodies in CaDI devices is solidly within the concentration ranges of SARS-CoV-2 specific antibodies found in COVID-19 patients (1-10 ng/ml based on well-plate ELISA assays), 26,27 indicating that the serological CaDI assay can provide potentially clinically useful data. Future iterations of the device will use electrochemical sensing as a more quantitative alternative to colorimetric detection.…”