Persistence of humoral response upon SARS‐CoV‐2 infection

Abstract

Summary SARS‐CoV‐2 continues to leave its toll on global health and the economy. Management of the pandemic will rely heavily on the degree of adaptive immunity persistence following natural SARS‐CoV‐2 infection. Along with the progression of the pandemic, more literature on the persistence of the SARS‐CoV‐2‐specific antibody response is becoming available. Here, we summarize findings on the persistence of the humoral, including neutralizing antibody, response at three to eight months post SARS‐CoV‐2 infection in non‐pregnant adults. While the comparability of the literature is limited, findings on the detectability of immunoglobulin G class of antibodies (IgG) were most consistent and were reported in most studies to last for six to eight months. Studies investigating the response of immunoglobins M and A (IgM, IgA) were limited and reported mixed results, in particular, for IgM. The majority of studies observed neutralizing antibodies at all time points tested, which in some studies lasted up to eight months. The presence of neutralizing antibodies has been linked to protection from re‐infection, suggesting long‐term immunity to SARS‐CoV‐2. These neutralizing capacities may be challenged by emerging virus variants, but mucosal antibodies as well as memory B and T cells may optimize future immune responses. Thus, further longitudinal investigation of PCR‐confirmed seropositive individuals using sensitive assays is warranted to elucidate the nature and duration of a more long‐term humoral response.

Waning of IgG, Total and Neutralizing Antibodies 6 Months Post-Vaccination with BNT162b2 in Healthcare Workers

“…In COVID-19 naïve subjects, the decline of total antibodies at 6 months was lower (i.e., −54.7%) than the decline of IgG (i.e., −89.6%) or NAbs (−98.7%), while in seropositive participants, the decline of total antibodies and IgG at 6 months was quite similar (−74.8% versus −79.4%) and lower than the decline of NAbs (−98.7%). The distinct kinetics observed for the total antibody assays compared to IgG may be explained by the additional response of non-IgG antibody isotypes, which may persist several month post-vaccination [ 25 , 26 ]. On the other hand, in subjects who had already developed an immune response due to exposure to SARS-CoV-2 or occurrence of COVID-19 disease, the serological response following a de novo exposure to the antigen is mainly dominated by the IgG response while the IgM response is reduced, or even absent.…”

Kinetics of severe acute respiratory syndrome coronavirus 2 infection antibody responses

“…Human antibodies are divided into five isotypes according to their constant domain: Immunoglobulin (Ig)M, IgG, IgA, IgD, and IgE. Different isotypes play a diverse roles in the process of anti-viral infection according to the characteristics of their structure, generation time, distribution, and half-life (6).…”

“…S1 folds into the N-terminal domain (NTD), receptor-binding domain (RBD), and two C-terminal domains (CTDs) (5,6). The RBD of S1 interacts with human angiotensinconverting enzyme (hACE2) to promote fusion between the cell membrane and the virus envelope, and the virion can reproduce in the cells (3,(5)(6)(7)(8)(9)(10). Figure 1 shows a schematic diagram of the viral infection and replication.…”

Myocardial Injury Complicated by Systolic Dysfunction in a COVID-19-Positive Dog

“…Therefore, delayed sampling of our dog (more than two months after the onset of the dog’s clinical signs because of restrictions on owner movement due to their quarantine) represented a likely explanation for the concomitant positive serology and negative PCR reported herein [ 38 ]. Similar temporal issues have been reported to complicate the interpretation of diagnostic tests even in humans affected with COVID-19 [ 39 ], as viral load can be undetectable 20 days after onset of clinical signs [ 40 ] but SARS-CoV-2 neutralizing antibodies can persist from 6–8 months to more than 12 months in this species [ 41 , 42 , 43 , 44 ]. In the present case, the PCR negativity, interpreted in the light of the dog’s history and clinical, cardiological and serological findings, did not preclude us from suspecting COVID-19 as a likely trigger of underlying myocardial compromise.…”