February 2, 2021
Journal Watch.
How Long Does Immunity Last After Recovery from Mild COVID-19?
George Sakoulas, MD reviewing Rodda LB et al. Cell 2021 Jan 7 Gaebler C et al. Nature 2021 Jan 18
Two studies suggest the adaptive immune response in COVID-19 is durable and continues to be shaped by viral remnants.
Our understanding of the immunity naturally conferred through SARS-CoV-2 infection is critical for gaining control of the COVID-19 pandemic. Immunologic memory is based on activation, expansion, and differentiation of B and T lymphocytes with viral neutralizing properties. With reexposure, these reactivated cell lines coordinate to clear the virus, preventing or mitigating disease and reducing transmission. Is this response durable in the setting of COVID-19?
Rodda et al. examined plasma and peripheral blood cells from 15 patients who recovered from mild COVID-19 (median duration of symptoms, 13 days) and 17 healthy controls. COVID-19 induced SARS-CoV-2–specific IgG antibodies, neutralizing plasma, and memory B and T lymphocytes that persisted for ≥3 months. Memory B lymphocytes expressed neutralizing antibodies against SARS-CoV-2, and memory T cells produced immune-activating cytokines (particularly IL-2 and interferon-gamma). The authors conclude that these manifold changes in the adaptive immune response render patients protected against SARS-CoV-2 infection for
at least 3 months.Gaebler at al. assessed humoral memory responses in 87 patients at both 40 days and 6 months after SARS-CoV-2 infection (median duration of symptoms, 12 days). Neutralizing IgG against the SARS-CoV-2 spike protein receptor binding domain (RBD) were detectable in plasma but decreased by 80% at 6 months compared with 40 days; however, the number of memory B cells with RBD specificity did not change. These cells evolved such that antibodies expressed at 6 months had increased neutralizing potency and breadth as well as resistance to RBD mutations. This evolution appeared to be driven by persistent viral antigens; indeed, a separate analysis of intestinal biopsies from convalescent asymptomatic patients showed SARS-CoV-2 nucleic acids and antigens in the small bowel of 7 of 14 patients. The authors conclude that viral remnants continue to drive adaptive immune evolution, optimizing the humoral response over time.
COMMENT
These studies provide in-depth analysis of the adaptive immune response to SARS-CoV-2, demonstrating residual humoral and cellular immune protection lasting at least 3 months as well as ongoing immune stimulation that continues to shape the host response long after clinical infection. These findings suggest that
reinfection in immunocompetent individuals may be less likely than was initially feared. While viral antigen persistence may underlie long-lasting immunity, and perhaps preserve protection against SARS-CoV-2 variants, this protection may come at the price of “long-hauler” patients with persistent symptoms of COVID-19 driven by continued immune stimulation.At the time we reviewed the paper by Gaebler et al., its publisher noted that it was not in final form and that subsequent changes might be made.
EDITOR DISCLOSURES AT TIME OF PUBLICATION
Disclosures for George Sakoulas, MD at time of publication
Consultant/Advisory Board Paratek Pharmaceuticals; Cidara Therapeutics; Nabriva Pharmaceuticals
Speaker’s Bureau Allergan Pharmaceuticals; Melinta Therapeutics; Achaogen; Theravance Biopharma
Royalties UpToDate
Grant/Research Support NIH
Editorial Boards Antimicrobial Agents and Chemotherapy
CITATION(S):
Rodda LB et al. Functional SARS-CoV-2-specific immune memory persists after mild COVID-19. Cell 2021 Jan 7; 184:169. (Δεν είναι ορατοί οι σύνδεσμοι (links).
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Gaebler C et al. Evolution of antibody immunity to SARS-CoV-2. Nature 2021 Jan 18; [e-pub]. (Δεν είναι ορατοί οι σύνδεσμοι (links).
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