Result for
Tag: immunity
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[Pre-print, not peer-reviewed] Blood samples from 100 convalescent donors 6 months after their initial SARS-CoV-2 infection found that T-cell responses against SARS-CoV-2 were present in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 29, 2020
Robust Neutralizing Antibodies to SARS-CoV-2 Infection Persist for Months
Analysis of a serology dataset from patients admitted to a New York City hospital with confirmed or suspected SARS-CoV-2 infection (n=30,082) showed that the vast majority of individuals (~92%) had moderate-to-high titers (> 1:320) of anti-spike antibodies with 90% of seroconverters making detectable neutralizing antibodies. Additionally, antibody titers from a cohort of 121 plasma donors…
SARS-CoV-2 Neutralizing Antibody LY-CoV555 in Outpatients with Covid-19
A phase 2 randomized placebo-controlled trial (n=452) interim analysis found that patients who received a 2800mg dose of monoclonal antibody LY-CoV555 could reduce SARS-CoV-2 log viral load by 3.4-fold after 11 days compared to patients receiving placebo, corresponding to a 0.53 log viral load reduction (95% CI: -0.98 to -0.08). Other patients receiving a 700mg…
October 28, 2020
High Seroprevalence but Short-Lived Immune Response to SARS-CoV-2 Infection in Paris
[Pre-print, not peer reviewed] In a cohort of workers outside Paris, both the concentration (titer) and quality of antibodies against SARS-CoV-2 declined 4-8 weeks after sampling. Among a cohort of 1,847 active workers in the Paris conurbation in France, 11% were positive for IgG against SARS-CoV-2-specific protein and 9.5% had evidence of viral neutralization. After…
October 21, 2020
Seroprevalence of Anti‐SARS‐CoV‐2 Antibodies in COVID‐19 Patients and Healthy Volunteers up to Six Months Post Disease Onset
A study among patients who tested positive for SARS-CoV-2 by PCR reported an increase in the detection of antibodies against the SARS-CoV-2 receptor binding domain (RBD) and spike protein using ELISA rapidly during the acute phase after infection, with a peak in detection around week 3. The detection of IgG antibodies remained robust, with confirmed…
October 19, 2020
Herd Immunity and Implications for SARS-CoV-2 Control
An infection-based herd immunity approach, in which low-risk groups become infected while higher-risk groups are sheltered, has been proposed as a strategy for response to the SARS-CoV-2 pandemic. Omer et al. describe methods for estimating the herd immunity threshold and estimate a SARS-CoV-2 herd immunity threshold of 50-67%. Because most, if not all of the…
October 16, 2020
Cellular Immunity in COVID-19 Convalescents with PCR-Confirmed Infection but with Undetectable SARS-CoV-2–Specific IgG
Immunity to SARS-CoV-2 infection may be mediated through T-cells, even among those with undetectable levels of antibodies against the virus. A study of immune responses against severe SARS-CoV-2 among a group of convalescent, potential blood donors in Germany found T-cell immunity against SARS-CoV-2 in 78% of volunteers who had a PCR-confirmed SARS-CoV-2 infection but had…
October 15, 2020
Waning Antibody Responses in Asymptomatic and Symptomatic SARS-CoV-2 Infection
Geometric mean SARS-CoV-2 neutralizing antibody titers of 18 SARS-CoV-2 positive patients in South Korea decreased from 219.4 at 2 months to 143.7 at 5 months (p=0.03) after infection, indicating a waning antibody response. The decline was significantly associated with antibody levels at 2 months and happened more frequently in symptomatic patients who developed pneumonia (n=11),…
Healthcare Workers with Mild Asymptomatic SARS-CoV-2 Infection Show T Cell Responses and Neutralising Antibodies after the First Wave
[Pre-print, not peer reviewed] A cohort study of 136 healthcare workers in the UK found that 90% of the 76 workers with mild or asymptomatic SARS-CoV-2 infection had detectable neutralizing antibodies at the beginning of the lockdown and 66% of the same workers had them after 16-18 weeks. T-cell responses tended to be lower among…
October 7, 2020
Updating Herd Immunity Models for the U.S. in 2020 Implications for the COVID-19 Response
[Pre-print, not peer-reviewed] A modeling study found that accounting for variations in contact patterns throughout the US leads to a lower estimate of the threshold for herd immunity to SARS-CoV-2 compared to models that assume even mixing of populations. Sheils et al. (Oct 6, 2020). Updating Herd Immunity Models for the U.S. in 2020 Implications…
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