Systemic and mucosal antibody responses specific to SARS-CoV-2 during mild versus severe COVID-19

Abstract

Background: Whereas severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody tests are increasingly being used to estimate the prevalence of SARS-CoV-2 infection, the determinants of these antibody responses remain unclear.Objectives: Our aim was to evaluate systemic and mucosal antibody responses toward SARS-CoV-2 in mild versus severe coronavirus disease 2019 (COVID-19) cases.

Defining the features and duration of antibody responses to SARS-CoV-2 infection associated with disease severity and outcome

“…It is important to note that decreasing antibody levels do not necessarily indicate that all immunity will be lost. It is possible that local mucosal antibody production in the airways could help prevent or impede SARS-CoV-2-infection upon re-exposure (39). Even if serum antibodies wane to undetectable levels, memory B and T cells stimulated by infection could provide a faster or more effective response following future exposure.…”

The Proportion of SARS-CoV-2 Infections That Are Asymptomatic

“…In a study of 222 hospitalized patients in Wuhan, China, IgM and IgG antibodies to SARS-CoV-2 were first detected 3 and 4 days, respectively, after symptomatic onset of COVID-19 ( 79 ). In a study of 109 health care workers and 64 hospitalized patients in Zurich, Switzerland, the severity of illness seemed to affect how quickly SARS-CoV-2 antibodies appeared ( 80 ). Patients with severe COVID-19 had detectable SARS-CoV-2 antibody titers after symptom onset, but those with mild cases “remained negative or became positive [for SARS-CoV-2 antibodies] 12 to 14 days after symptom onset” ( 80 ).…”

“…In a study of 109 health care workers and 64 hospitalized patients in Zurich, Switzerland, the severity of illness seemed to affect how quickly SARS-CoV-2 antibodies appeared ( 80 ). Patients with severe COVID-19 had detectable SARS-CoV-2 antibody titers after symptom onset, but those with mild cases “remained negative or became positive [for SARS-CoV-2 antibodies] 12 to 14 days after symptom onset” ( 80 ). These data suggest that positive antibody test results are unlikely to occur during the period when it is uncertain whether an infected person is presymptomatic or asymptomatic.…”

A distinct innate immune signature marks progression from mild to severe COVID-19

“…We have previously described the SARS-CoV-2-specific antibody response in a subset of this cohort. 70 The complete characteristics of the cohort are given in Table 1 .…”