SARS-CoV-2 Antibody Responses Do Not Predict COVID-19 Disease Severity

Abstract

Objectives Initial reports indicate adequate performance of some serology-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) assays. However, additional studies are required to facilitate interpretation of results, including how antibody levels impact immunity and disease course. Methods A total of 967 subjects were tested for IgG antibodies reactive to SARS-CoV-2, including 172 suspected cases of SARS-CoV-2, 656 plasma samples from healthy donors, 49 sera from patients with rheumatic disease, and 90 specimens from individuals positive for polymerase chain reaction (PCR)–based respiratory viral panel. A subgroup of SARS-CoV-2 PCR-positive cases was tested for IgM antibodies by proteome array method. Results All specificity and cross-reactivity specimens were negative for SARS-CoV-2 IgG antibodies (0/795, 0%). Positive agreement of IgG with PCR was 83% of samples confirmed to be more than 14 days from symptom onset, with less than 100% sensitivity attributable to a case with severe immunosuppression. Virus-specific IgM was positive in a higher proportion of cases less than 3 days from symptom onset. No association was observed between mild and severe disease course with respect to IgG and IgM levels. Conclusions The studied SARS-CoV-2 IgG assay had 100% specificity and no adverse cross-reactivity. Measures of IgG and IgM antibodies did not predict disease severity in our patient population.

Testing-on-a-probe biosensors reveal association of early SARS-CoV-2 total antibodies and surrogate neutralizing antibodies with mortality in COVID-19 patients

“…Multiple studies have shown that SARS-CoV-2 specific antibody levels, such as IgM, IgG or NAb are elevated in patients with a more severe disease courses ( Lynch et al, 2020 ; Wang et al, 2020a ; Wang et al, 2020b ; Zhou et al, 2020 ; Zohar and Alter, 2020 ). However, a few other publications have reported no significant differences in SARS-CoV-2 antibody responses between severe and non-severe patients ( Phipps et al, 2020 ; Ren et al, 2020 ). These discrepancies could be due to a variety of factors, including the patient populations, the definitions of disease severity, the serology assays used, the isotypes of antibody or target epitopes being detected, and the timing in the disease course when the antibody testing is performed.…”

ELISA detection of SARS-CoV-2 antibodies in saliva

“…This may explain our results, although it is important to note that this link is not confirmed, with Phipps et al . 20 seeing no association between IgG level and severity of disease in their patient population. Further, these studies are all investigating serum IgG; saliva IgG may present differently and has yet to be fully investigated.…”

Convalescent plasma anti–SARS-CoV-2 spike protein ectodomain and receptor-binding domain IgG correlate with virus neutralization

“…The ELISA used to measure anti-S IgG antibodies in donor serum specimens was performed as follows. Briefly, ECD-purified recombinant protein used comprises amino acid residues 1-1208, and the RBD comprises amino acids 319-591 of SARS-CoV-2 S pro-previous studies of patients with SARS and dengue hemorrhagic fever (30) but contrasts with a recent report analyzing patients with COVID-19 (31). It is possible that differences in antibody testing platforms account for the contrasting observations.…”