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| Charlotte Thålin, M.D. and associate professor at the Department of Clinical Sciences, Danderyd Hospital Photo Credit: Ludvig Kostyal |
Researchers hope that a nasal vaccine may generate mucosal immune responses that protect against SARS-CoV-2 infection.
High levels of mucosal IgA antibodies in the airways protect against SARS-CoV-2 infection for at least eight months. Omicron infection generates durable mucosal antibodies, reducing the risk of re-infection. These are the findings of a study published in The Lancet Infectious Diseases by researchers at Karolinska Institutet and Danderyd Hospital in Sweden. The results raise further hope for the feasibility of future nasal vaccine platforms to protect against infection.
“Antibodies in the blood protect from severe disease, but if we aim to limit infection, viral transmission and the emergence of new SARS-CoV-2 variants, we need to reinforce our immunity at the mucosal surface, which is the viral point of entry”, says Charlotte Thålin, M.D. and associate professor at the Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet who led the study. “This is not achieved by currently employed intramuscularly-delivered vaccines. But the hope is that a nasal vaccine may generate mucosal immune responses similar to those seen after infection, and thereby block the transmission chain”.
The researchers have also investigated the impact of repeated infections and found that participants with a prior SARS-CoV-2 infection generated a stronger mucosal immune response to Omicron breakthrough infection.
Development of nasal vaccines
“The results show us that it is possible to recall protective and durable mucosal IgA antibody responses in the airways, and that these responses increase with the number of infections. Although these findings are not surprising, they are important for the development of nasal vaccines”, says Ulrika Marking, M.D., PhD student at Karolinska Institutet and first author of the paper.
The COMMUNITY study continues with regular samplings from blood and mucosa, monitoring immune responses after repeated SARS-CoV-2 infections and vaccinations. The study is being conducted in close collaboration between Danderyd Hospital, Karolinska Institutet, Uppsala University, the Public Health Agency of Sweden, KTH Royal Institute of Technology, and SciLifeLab.
The research has been funded by the Jonas and Christina af Jochnick Foundation, the Public Health Agency of Sweden, Region Stockholm, the Knut and Alice Wallenberg Foundation, Leif Lundblad and family, the Swedish Research Council, the Swedish Heart-Lung Foundation, the Bill and Melinda Gates Foundation, Karolinska Institutet and SciLifeLab.
Published in journal: The Lancet Infectious Diseases
Source/Credit: Karolinska Institutet
Reference Number: vi011623_01