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.
BackgroundMost 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.MethodsIn 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.FindingsStrong and consistent nasal anti-NP and anti-S IgA responses were demonstrated, which remained elevated for nine months (p InterpretationThe decline in nasal IgA responses 9 months after infection and minimal impact of subsequent vaccination may explain the lack of long-lasting nasal defence against reinfection and the limited effects of vaccination on transmission. These findings highlight the need to develop vaccines that enhance nasal immunity.FundingThis study has been supported by ISARIC4C and PHOSP-COVID consortia. ISARIC4C is supported by grants from the National Institute for Health and Care Research and the Medical Research Council. Liverpool Experimental Cancer Medicine Centre provided infrastructure support for this research. The PHOSP-COVD study is jointly funded by UK Research and Innovation and National Institute of Health and Care Research. The funders were not involved in the study design, interpretation of data or the writing of this manuscript.