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The following is a summary of “Early, robust mucosal secretory IgA but not IgG response to SARS-CoV-2 spike in oral fluid is associated with faster viral clearance and COVID-19 symptom resolution,” published in the September 2024 issue of Infectious Disease by Pisanic et al.
Mucosal COVID-19 vaccine development is a priority, but there is limited understanding of mucosal immunity’s role in disease progression and how to assess mucosal vaccine immunogenicity.
Researchers conducted a retrospective study to analyze the role of oral mucosal antibody responses in viral clearance and COVID-19 symptom duration.
They recruited participants with PCR-confirmed SARS-CoV-2 infection and collected oral fluid samples for SARS-CoV-2 antibody multiplex assays, nasal swabs for RT-PCR, and symptom information at up to 8 follow-up visits from April 2020 to February 2022.
The results showed high and moderate oral fluid anti-spike (S) secretory IgA (SIgA) post-infection were associated with faster viral clearance (14 days earlier) and symptom resolution (9-10 days earlier) across all age groups, with effect sizes comparable to COVID-19 vaccine immunity, delayed and higher anti-S IgG levels were linked to longer time to clearance and recovery. Lower anti-RBD SIgA levels were related to experiencing symptoms for more than 4 weeks 15-30 days after infection onset (P<0.001).
They concluded early mucosal SIgA levels facilitated faster clearance of SARS-CoV-2 and symptom recovery, highlighting the need for standardized assays to evaluate novel mucosal vaccines.
Source: academic.oup.com/jid/advance-article/doi/10.1093/infdis/jiae447/7756371
