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Tag: antibodies
November 20, 2020
Antibodies to SARS-CoV-2 are associated with protection against Reinfection
[Pre-print, not peer reviewed] A prospective longitudinal cohort study of healthcare workers shows that antibodies against the spike protein of SARS-CoV-2 (suggesting previous infection) are associated with lower risk of a PCR-positive test (IRR: 0.24, 95% CI: 0.08-0.76). The study included 11,052 seronegative individuals and 1,246 seropositive individuals. No symptomatic infections and only three asymptomatic…
November 17, 2020
Immunological Memory to SARS-CoV-2 Assessed for Greater than Six Months after Infection
[Pre-print, not peer reviewed] Different components of the immune memory against SARS-CoV-2 exhibited distinct kinetics over time in a cross-sectional study of 185 recovered COVID-19 cases. Spike IgG levels were relatively stable over >6 months, memory B cells were more abundant at 6 months than at 1 month, and CD8+ and CD4+ T cells declined…
Estimating the Cumulative Incidence of SARS-CoV-2 Infection and the Infection Fatality Ratio in Light of Waning Antibodies
[Pre-print, not peer reviewed] The cumulative incidence of SARS-CoV-2 infection may be underestimated by using cross-sectional data from serology tests without adjusting for waning antibodies. By estimating the average time from seroconversion to seroreversion and combining with population-level cross sectional data, Shioda et al. calculated the cumulative incidence to be 27% in New York City…
November 13, 2020
Diagnosis and Tracking of Past SARS-CoV-2 Infection in a Large Study of Vo’ Italy Through T-Cell Receptor Sequencing
[Pre-print, not peer-reviewed] The presence of T-cells reactive to SARS-CoV-2 was found to be a strong indicator of past SARS-CoV-2 infection. In a large population study (n = 2,200) in Italy that included 70 individuals with PCR-confirmed SARS-CoV-2 infection, blood samples taken 60 days after PCR diagnosis indicated that 97% of the people with PCR-confirmed…
November 6, 2020
Viral RNA Level, Serum Antibody Responses, and Transmission Risk in Recovered COVID-19 Patients with Recurrent Positive SARS-CoV-2 RNA Test Results: A Population-Based Observational Cohort Study
Intermittent excretion of low levels of SARS-CoV-2 RNA after hospital discharge was not associated with either secondary transmission or worsening clinical disease. A population-based observational study of patients in China who had clinically recovered from SARS-CoV-2 and satisfied criteria for discharge including two negative PCR tests were then re-tested as outpatients. 479 patients were found…
Distinct Antibody Responses to SARS-CoV-2 in Children and Adults across the COVID-19 Clinical Spectrum
A study of children and adults with SARS-CoV-2 infection in New York found that there are different antibody responses between adult and pediatric populations. Cohorts of adults with COVID-19 had anti-spike IgG, IgM and IgA antibodies, as well as anti-nucleocapsid IgG antibody, while children with and without multisystem inflammatory syndrome (MIS-C) predominantly generated IgG antibodies…
November 5, 2020
Lack of Antibodies to SARS-CoV-2 in a Large Cohort of Previously Infected Persons
A total of 6.3% of 2,547 healthcare workers and first responders in the New York City and Detroit metropolitan areas with previous confirmed SARS-CoV-2 infection were seronegative. Among symptomatic persons, the proportion seronegative was largely stable between 2 weeks and 90 days following symptom onset. The proportion seronegative ranged from 0% among 79 persons previously…
November 3, 2020
Robust SARS-CoV-2-Specific T-Cell Immunity Is Maintained at 6 Months Following Primary Infection
[Pre-print, not peer-reviewed] Blood samples from 100 convalescent donors 6 months after their initial SARS-CoV-2 infection found that T-cell responses against SARS-CoV-2 were present in all donors. The median response was 50% higher among donors with an initial symptomatic infection. T-cell responses to both spike and nucleoprotein/membrane proteins strongly correlated with peak antibody levels against…
October 28, 2020
Declining Prevalence of Antibody Positivity to SARS-CoV-2 a Community Study of 365000 Adults
[Pre-print, not peer reviewed] Results from 3 non-overlapping cohorts in the UK demonstrated that the overall prevalence of detectable IgG antibodies against SARS-CoV-2 declined by 27% (from 6.0% to 4.4%) between late June and September 2020. Greater levels of decline were seen among older people aged 75+ years (-39%) compared to those 18-24 years old…
October 27, 2020
Longitudinal Observation and Decline of Neutralizing Antibody Responses in the Three Months Following SARS-CoV-2 Infection in Humans
A longitudinal study that followed 65 SARS-CoV-2 infected individuals up to 94 days post onset of symptoms found that the neutralizing antibody (nAb) response to SARS-CoV-2 is typical of an acute viral infection, with an initial peak whose magnitude is dependent upon disease severity, followed by declining titers. Some infected individuals with a high peak…
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