SARS-CoV-2-specific nasal IgA wanes 9 months after hospitalisation with COVID-19 and is not induced by subsequent vaccination.
Liew F., Talwar S., Cross A., Willett BJ., Scott S., Logan N., Siggins MK., Swieboda D., Sidhu JK., Efstathiou C., Moore SC., Davis C., Mohamed N., Nunag J., King C., Thompson AAR., Rowland-Jones SL., Docherty AB., Chalmers JD., Ho L-P., Horsley A., Raman B., Poinasamy K., Marks M., Kon OM., Howard L., Wootton DG., Dunachie S., Quint JK., Evans RA., Wain LV., Fontanella S., de Silva TI., Ho A., Harrison E., Baillie JK., Semple MG., Brightling C., Thwaites RS., Turtle L., Openshaw PJM., ISARIC4C Investigators None., PHOSP-COVID collaborative group None.
BACKGROUND: Most studies of immunity to SARS-CoV-2 focus on circulating antibody, giving limited insights into mucosal defences that prevent viral replication and onward transmission. We studied nasal and plasma antibody responses one year after hospitalisation for COVID-19, including a period when SARS-CoV-2 vaccination was introduced. METHODS: In this follow up study, plasma and nasosorption samples were prospectively collected from 446 adults hospitalised for COVID-19 between February 2020 and March 2021 via the ISARIC4C and PHOSP-COVID consortia. IgA and IgG responses to NP and S of ancestral SARS-CoV-2, Delta and Omicron (BA.1) variants were measured by electrochemiluminescence and compared with plasma neutralisation data. FINDINGS: Strong and consistent nasal anti-NP and anti-S IgA responses were demonstrated, which remained elevated for nine months (p