Antibody response to COVID-19 foreshadows outcomes

The presence of neutralizing antibodies targeting the SARS-CoV-2 protein seems to predict the outcomes of the novel coronavirus disease (COVID-19), a recent study has found.

“Our results thus suggest compromised immune responses to the SARS-CoV-2 spike to be a major trait of COVID-19 patients with critical conditions, and thereby inform on the planning of COVID-19 patient care and therapy prioritization,” the researchers said.

They enrolled 162 symptomatic COVID-19 patients (median age 63 years, 66.7 percent male) followed for 8 months from symptom onset. A lentiviral-based SARS-CoV-2 neutralization assay was used to measure the neutralizing antibody (nAb) response, which found a highly heterogeneous early nAb response.

For instance, of all samples collected within the first week, 43.2 percent displayed such a response, which increased to 78.9 percent among samples collected within the second week from symptom onset. In contrast, 28.7 percent of patients had no detectable nAbs.

At the 42-day visit, nAb response continued to increase in most patients; by day 99, nAbs had declined, such that complete loss was documented in three patients. Only 46 patients attended visits at or beyond 6 months, but in all cases, nAb titres were even more diminished, suggesting decay over time.

The researchers also found that nAb response and kinetics correlated with disease course. For example, the early development of nAbs was significantly correlated with a quicker virus clearance, as expressed by a quicker time to a negative swab (p=0.002). On the other hand, the lack of an early nAb response emerged as a strong predictor of death (p=0.008).