%0 Journal Article
%T Lower Humoral and Cellular Immunity Following Asymptomatic SARS-CoV-2 Infection Compared to Symptomatic Infection in Education (The ACE Cohort).
%A Hopkins G
%A Gomez N
%A Tucis D
%A Bartlett L
%A Steers G
%A Burns E
%A Brown M
%A Harvey-Cowlishaw T
%A Santos R
%A Lauder SN
%A Scurr M
%A Capitani L
%A Burnell S
%A Rees T
%A Smart K
%A Somerville M
%A Gallimore A
%A Perera M
%A Potts M
%A Metaxaki M
%A Krishna B
%A Jackson H
%A Tighe P
%A Onion D
%A Godkin A
%A Wills M
%A Fairclough L
%J J Clin Immunol
%V 44
%N 6
%D 2024 Jun 10
%M 38856804
%F 8.542
%R 10.1007/s10875-024-01739-0
%X <B>OBJECTIVE: </B>Asymptomatic SARS-CoV-2 infections were widely reported during the COVID-19 pandemic, acting as a hidden source of infection. Many existing studies investigating asymptomatic immunity failed to recruit true asymptomatic individuals. Thus, we conducted a longitudinal cohort study to evaluate humoral- and cell-mediated responses to infection and vaccination in well-defined asymptomatic young adults (the Asymptomatic COVID-19 in Education [ACE] cohort).<BR><B>METHODS: </B>Asymptomatic testing services located at three UK universities identified asymptomatic young adults who were subsequently recruited with age- and sex-matched symptomatic and uninfected controls. Blood and saliva samples were collected after SARS-CoV-2 Wuhan infection, and again after vaccination. 51 participant's anti-spike antibody titres, neutralizing antibodies, and spike-specific T-cell responses were measured, against both Wuhan and Omicron B.1.1.529.1.<BR><B>RESULTS: </B>Asymptomatic participants exhibited reduced Wuhan-specific neutralization antibodies pre- and post-vaccination, as well as fewer Omicron-specific neutralization antibodies post-vaccination, compared to symptomatic participants. Lower Wuhan and Omicron-specific IgG titres in asymptomatic individuals were also observed pre- and post-vaccination, compared to symptomatic participants. There were no differences in salivary IgA levels. Conventional flow cytometry analysis and multi-dimensional clustering analysis indicated unvaccinated asymptomatic participants had significantly fewer Wuhan-specific IL-2 secreting CD4+ CD45RA+ T cells and activated CD8+ T cells than symptomatic participants, though these differences dissipated after vaccination.<BR><B>CONCLUSIONS: </B>Asymptomatic infection results in decreased antibody and T cell responses to further exposure to SARS-CoV-2 variants, compared to symptomatic infection. Post-vaccination, antibody responses are still inferior, but T cell immunity increases to match symptomatic subjects, emphasising the importance of vaccination to help protect asymptomatic individuals against future variants.