Tear antibodies to SARS-CoV-2: implications for transmission

Objectives SARS-CoV-2 can be transmitted by aerosols and the ocular surface may be an important route of transmission. Little is known about protective antibody responses to SARS-CoV-2 in tears after infection or vaccination. We analysed SARS-CoV-2 specific IgG and IgA responses in human tears after either COVID-19 infection or vaccination. Methods We recruited 16 subjects with COVID-19 infection an average of 7 months previously and 15 subjects before and 2 weeks after Comirnaty (Pfizer-BioNtech) vaccination. Plasma, saliva and basal tears were collected. Pre-pandemic plasma, saliva and basal tears from 11 individuals were included as healthy controls. Antibody responses to 5 SARS-CoV-2 antigens were measured via multiplex. Results IgG antibodies to Spike and Nucleoprotein were detected in tears, saliva and plasma from subjects with prior SARS-CoV-2 infection in comparison to uninfected controls. While RBD-specific antibodies were detected in plasma, minimal RBD-specific antibodies were detected in tears and saliva. In contrast, high levels of IgG antibodies to Spike and RBD, but not Nucleoprotein, were induced in tears, saliva and plasma of subjects receiving 2 doses of the Comirnaty vaccine. Increased levels of IgA1 and IgA2 antibodies to SARS-CoV-2 antigens were detected in plasma following infection or vaccination, but were unchanged in tears and saliva. Conclusion Both infection and vaccination induce SARS-CoV-2-specific IgG antibodies in tears. RBD-specific IgG antibodies in tears were induced by vaccination but were not present 7 months post-infection. This suggests neutralising antibodies may be low in the tears late following infection.