937 – Lack of Association of SARS-CoV-2 N- and S-Antigenemia With Long COVID, 2025, Antar et al

937 – Lack of Association of SARS-CoV-2 N- and S-Antigenemia With Long COVID

Annukka Antar, Perrine Lallemand, Zoe O. Demko, Armaan Jamal, Nuria Gallego Marquez, Tamilore Adeagbo, Selin Akbas, Elizabeth Pasetes, Paul Blair, Katy Shaw-Saliba, Andrea Cox, Michael Peluso, Robin Dewar, Alan Landay, Yukari Manabe

Background
The pathobiology of long COVID (LC) remains unknown, and many hypothesize that persistent viral antigen sustains long COVID. While there have been reports documenting viral protein and RNA many months after SARS-CoV-2 infection, it is not yet clear whether persistent viral antigen is associated with long COVID.

Methods
SARS-CoV-2 nucleocapsid (N) antigen levels were quantified from a cohort of 214 individuals (cohort 1) aged 15 and older with first SARS-CoV-2 infection confirmed by RT-PCR between April 2020 and April 2022. A total of 466 plasma samples from 1 month (n=149 individuals), 3 months (n=44), 6 months (n=76), 12 months (n=80), 18 months (n=59), and 24 months (n=58) post infection were assessed. Plasma SARS-CoV-2 N antigen levels were determined using the quantitative Simoa SARS-CoV-2 N Protein Advantage kit and HD-X instrument (Quanterix). 90 µL of plasma were run in duplicate.

In a nonoverlapping cohort of 214 different individuals (cohort 2, n=147 with first SARS-CoV-2 infection between June 2021 and August 2022, n=67 with no prior COVID-19), SARS-CoV-2 spike (S) and N antigen were assessed using antigen-capture immunogenicity assay (Meso Scale Discovery, MSD). Plasma from 1- and 4-months post-infection was assessed for those with recent infection. In both cohorts, LC was defined as reporting any symptom and also reporting not returning to usual pre-COVID health at 3+ months. Mann Whitney U test was used to assess group differences.

Results
Over 97% of participants in each cohort did not require hospitalization for acute COVID-19. All 466 plasma samples assessed for N antigen by Quanterix assay were negative (<3 pg/mL), except at 1-month post-infection in one individual with severe immunosuppression, despite half of participants with surveys completed 3+ months post-infection having LC.

Levels of S and N antigen assessed by MSD in the second cohort did not differ at 1- or 4-months post-infection in people who ever vs never had LC (medians, S antigen: M1 LC 0.089 pg/mL vs M1 quick recovery [QR] 0.081; M4 LC 0.082 vs M4 QR 0.099; N antigen: M1 LC 0.027 vs M1 QR 0.034; M4 LC 0.024 vs M4 QR 0.026), nor did levels of S and N antigen differ at 1-month post-infection between people who never had COVID-19 vs LC (never COVID S antigen: 0.086, N antigen: 0.024).

Conclusions
Using two assay methodologies and longitudinal samples from two cohorts of people with mild to moderate acute SARS-CoV-2, we did not identify a relationship between persistent plasma antigenemia and LC.

Link (Conference on Retroviruses and Opportunistic Infections) [Abstract Only]