Nina Le BertWan Ni ChiaWei Yee WanAlvin Kuo Jing TeoSamuel Zeng Rong ChongNicole TanDoreen Soek Chin TanAdeline ChiaIain Beehuat TanKamini KunasegaranQin Xuan ChuaMohammad Yazid AbdadAven Shan Hua NgShawn VasooJulian Xiao Li AngMao Sheng LeeLouisa SunJinyan FangFeng ZhuAlex R. CookTar Choon AwJingxiang HuangClarence TamFong Sin LeeHannah ClaphamEnan Jun Kang GohMonica Socheata Suor PeouShiow Pin TanSiew Kim OngLin Fa WangAntonio BertolettiLi Yang HsuBiauw Chi OngNational Centre for Infectious DiseasesFaculty of Tropical Medicine, Mahidol UniversityNational Cancer Centre, SingaporeA-Star, Genome Institute of SingaporeSingapore General HospitalNational University of SingaporeNuffield Department of MedicineAlexandra Hospital, SingaporeSengkang General Hospital2022-08-042022-08-042021-01-01Emerging Microbes and Infections. Vol.10, No.1 (2021), 2141-2150222217512-s2.0-85119251667https://repository.li.mahidol.ac.th/handle/20.500.14594/77339Background: We studied humoral and cellular responses against SARS-CoV-2 longitudinally in a homogeneous population of healthy young/middle-aged men of South Asian ethnicity with mild COVID-19. Methods: In total, we recruited 994 men (median age: 34 years) post-COVID-19 diagnosis. Repeated cross-sectional surveys were conducted between May 2020 and January 2021 at six time points–day 28 (n = 327), day 80 (n = 202), day 105 (n = 294), day 140 (n = 172), day 180 (n = 758), and day 280 (n = 311). Three commercial assays were used to detect anti-nucleoprotein (NP) and neutralizing antibodies. T cell response specific for Spike, Membrane and NP SARS-CoV-2 proteins was tested in 85 patients at day 105, 180, and 280. Results: All serological tests displayed different kinetics of progressive antibody reduction while the frequency of T cells specific for different structural SARS-CoV-2 proteins was stable over time. Both showed a marked heterogeneity of magnitude among the studied cohort. Comparatively, cellular responses lasted longer than humoral responses and were still detectable nine months after infection in the individuals who lost antibody detection. Correlation between T cell frequencies and all antibodies was lost over time. Conclusion: Humoral and cellular immunity against SARS-CoV-2 is induced with differing kinetics of persistence in those with mild disease. The magnitude of T cells and antibodies is highly heterogeneous in a homogeneous study population. These observations have implications for COVID-19 surveillance, vaccination strategies, and post-pandemic planning.Mahidol UniversityImmunology and MicrobiologyMedicinePharmacology, Toxicology and PharmaceuticsArticleSCOPUS10.1080/22221751.2021.1999777