Primary Omicron infection elicits weak antibody response but robust cellularimmunity in children

Dowell, A. C.; Lancaster, T.; Bruton, R.; Ireland, G.; Bentley, C.; Sylla, P.; Zuo, J.; Scott, S.; Jardin, A.; Begum, J.; Roberts, T.; Stephens, C.; Amin, U.; Ditta, S.; Shepherdson, R.; Powell, A.; Brent, A.; Brent, B.; Baawuah, F.; Okike, I.; Beckmann, J.; Ahmad, S.; Aiano, F.; Garstang, J.; Ramsay, M.; Azad, R.; Waiblinger, D.; Willet, B.; Wright, J.; Ladhani, S.; Moss, P.

doi:10.1101/2022.07.26.501570

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bioRxiv · 10.1101/2022.07.26.501570

Primary Omicron infection elicits weak antibody response but robust cellularimmunity in children

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Abstract

Omicron variants of SARS-CoV-2 are globally dominant and infection rates are very high in children. We determined immune responses following Omicron BA.1/2 infection in children aged 6-14 years and related this to prior and subsequent SARS-CoV-2 infection or vaccination. Primary Omicron infection elicited a weak antibody response with poor functional neutralizing antibodies. Subsequent Omicron reinfection or COVID-19 vaccination elicited increased antibody titres with broad neutralisation of Omicron subvariants. Prior pre-Omicron SARS-CoV-2 virus infection or vaccination primed for robust antibody responses following Omicron infection but these remained primarily focussed against ancestral variants. Primary Omicron infection thus elicits a weak antibody response in children which is boosted after reinfection or vaccination. Cellular responses were robust and broadly equivalent in all groups, providing protection against severe disease irrespective of SARS-CoV-2 variant. Immunological imprinting is likely to act as an important determinant of long-term humoral immunity, the future clinical importance of which is unknown.

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Dowell, A. C., Lancaster, T., Bruton, R., Ireland, G., Bentley, C., Sylla, P., Zuo, J., Scott, S., Jardin, A., Begum, J., Roberts, T., Stephens, C., Amin, U., Ditta, S., Shepherdson, R., Powell, A., Brent, A., Brent, B., Baawuah, F., Okike, I., Beckmann, J., Ahmad, S., Aiano, F., Garstang, J., Ramsay, M., Azad, R., Waiblinger, D., Willet, B., Wright, J., Ladhani, S., Moss, P.. 2022-07-26. Primary Omicron infection elicits weak antibody response but robust cellularimmunity in children. https://doi.org/10.1101/2022.07.26.501570

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