SARS-CoV-2 antibody dynamics and B-cell memory response over time in COVID-19 convalescent subjects

Abstract

Objectives Worldwide spread of COVID-19 disease highlights the need for assessment of long-term humoral immunity in convalescent subjects. Our objectives were to evaluate long-term IgG SARS-CoV-2 antibody response and B-cell memory response in COVID-19 convalescent subjects. Methods Blood samples were collected from a cohort of subjects recovering from COVID-19 disease and from healthy subjects that donated blood. SARS-CoV-2 IgG antibodies were quantitatively detected by ELISA using anti-S1 spike IgG. SARS-CoV-2 spike-specific IgG memory B-cells were evaluated in a randomly selected group of COVID-19 recovering subjects by reversed B-cell FluroSpot based on human IgG SARS-CoV-2 receptor-binding domain. Statistical analysis was performed with clinical variables and time post-COVID-19 infection. Results Antibody response was not detected in 26 of 392 (6.6%) COVID-19 convalescent subjects. Over a period of 9 months, the level of antibodies decreased by 50% but stabilized at 6 months and prevailed a protective level up to 9 months. No differences were found regarding IgG SARS-COV-2 antibody levels for age, gender, and major blood types, over-time. COVID-19 asymptomatic subjects did not differ in antibody level overtime from subjects with mild to severe disease. Repeated paired IgG SARS-COV-2 antibody level analyses disclosed that over 6 and 9 months, 15.3% (9 of 59) and 15.8% (3 of 19) of subjects became SARS-COV-2 IgG seronegative, respectively, all with low antibody level at 3 months. Rate of antibody decline was not affected by age, gender, or clinical symptomatology. In a subgroup of recovering subjects, memory B-cell response up to 9-months post COVID-19 infection, was undetectable in 31.8% (14/44) of subjects with no correlation to age, SARS-COV-2 antibody level, or time post-infection. Conclusions Majority of COVID-19 convalescent subjects develop IgG SARS-COV-2 antibody response that prevails a protective level over a period of up to 9-months regardless of age, gender, major blood types or clinical symptomatology.

Exploring Rapid and Effective Screening Methods for Anti-SARS-CoV-2 Neutralizing Antibodies in COVID-19 Convalescent Patients and Longitudinal Vaccinated Populations

“…In this study, we found that there were no differences in age, gender, and disease stages in antibody responses. This result is consistent with the previous longitudinal study [12,34,35]. Seropositivity rate (99.5%) was found at 6 months after infection [12], and 95.8% was identified in the follow-up 10 months after infection [13].…”

The duration and specificity of the humoral immune response to SARS-CoV-2

“…Repeated paired analyses of the level of IgG antibodies to SARS-COV-2 showed that after 6 and 9 months, only 15.3 % (9 of 59) and 15.8 % (3 of 19) of subjects became seronegative to SARS-COV-2 IgG, respectively. It is noteworthy that all those seronegative showed low levels of antibodies as early as 3 months after the disease [2]. Similar data can be found in other reports [7,9,11].…”

Blunted Post-COVID-19 Humoral Immunity in Patients With CNS Demyelinating Disorders on Anti-CD20 Treatments

“…This is similar to most case series and small cohort studies of patients with CNS demyelinating disorders around the world (5-8). However, it is drastically lower than the >90% seropositivity within the first 6 months post-infection in the general population and the 76-80% observed in two recent international cohorts (1,3,9,10,15). As we observed a lower seropositivity rate in patients not on a Prior COVID-19 infection severity, patient characteristics, and durations between infection and antibody collection are listed above for patients found to have a persistently positive COVID-19 IgG over time.…”

“…Several studies have demonstrated both humoral and cellular immunity are formed after COVID-19 infection in >90% of the general population, although the duration remains debated (1)(2)(3)(4). Patients with multiple sclerosis (MS) and other CNS demyelinating disorders have been found in cohort studies to have an average rate of post-infection seropositivity between 41 and 80% (5)(6)(7)(8)(9)(10).…”