Abstract

Research on long-term follow-up in individuals who have recovered from coronavirus disease-19 (COVID-19) would yield insights regarding their immunity status and identify those who need booster vaccinations. This study evaluated the longevity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific cellular and humoral memory responses, as well as T cell effector functionalities, at 1-2 months ( = 40), 8-9 months ( = 40), and 12 months/1 year ( = 27) following recovery from SARS-CoV-2 infection. CTL response by enzyme-linked immunospot (ELISPOT); levels of cytokine by Bio-Plex, natural killer (NK), CD4+ helper, and CD8+ cytotoxic T cell functionalities using flow cytometry; anti-SARS-CoV-2 IgG by ELISA; and levels of neutralizing antibodies (NAbs) by surrogate virus NAb assay were assessed. The levels of SARS-CoV-2-specific IgG and NAb at 1-2 and 8-9 months postrecovery were hand in hand and appeared declining. SARS-CoV-2-specific B, memory B and plasma cells, and T cells sustained up to 8-9 months. Increased expression of CD107a/IFN-γ by NK cells and cytotoxic T cells at 8-9 months could be indicative of SARS-CoV-2-specific effector functions. Recovered individuals with positive and negative IgG antibody status displayed T cell response up to 1 year and 8-9 months, respectively, emphasizing the durabilty of effector immunity up to 8-9 months regardless of IgG antibody status. Overall, the recovered individuals exhibited robust immunological memory, sustained T cell response with effector functionality against SARS-CoV-2 that persists for at least 8-9 months.

MeSH

Cells, Flow Cytometry, Coronavirus, Sars-Cov-2, Recycling, Covid-19, Immune System Diseases, Immunologic Memory, Viruses, Immunity, Severe Acute Respiratory Syndrome-Related Coronavirus, Memory, T-Lymphocytes

Cited by

• NK Cells: A Powerful Squad Versus SARS-CoV-2. Int J Mol Sci, 2025