Result for
Tag: immunity
January 7, 2021
Immunological Memory to SARS-CoV-2 Assessed for up to 8 Months after Infection
IgG antibodies against the Spike protein and the receptor binding domain (RBD) were relatively stable over 6 months in a cohort study of individuals with confirmed COVID-19 (n=188). Among 40 individuals with blood samples 6-8 months post-symptom onset, 90%, 88%, and 90% remained seropositive for anti-spike IgG, anti-RBD IgG, and neutralizing antibodies, respectively. Paired timepoint…
January 6, 2021
Estimation of US SARS-CoV-2 Infections, Symptomatic Infections, Hospitalizations, and Deaths Using Seroprevalence Surveys
A cross-sectional study using data from both public health surveillance records of reported COVID-19 cases and seroprevalence surveys found that an estimated 46,910,006 SARS-CoV-2 infections, 28,122,752 symptomatic infections, 956,174 hospitalizations, and 304,915 deaths occurred in the US through November 15, 2020. The authors note that 14% of the US population was infected with SARS-CoV-2 by…
The Duration, Dynamics and Determinants of SARS-CoV-2 Antibody Responses in Individual Healthcare Workers
A longitudinal SARS-CoV-2 seroprevalence study of healthcare workers in the United Kingdom found peak IgG antibody levels to SARS-CoV-2 nucleocapsid was 24 days following the first positive PCR test with a mean antibody half-life of 85 days. Antibodies waned faster in younger adults and those without symptoms. Anti-spike IgG levels remained stably detected after a…
January 5, 2021
Comprehensive Mapping of Mutations to the SARS-CoV-2 Receptor-Binding Domain That Affect Recognition by Polyclonal Human Serum Antibodies
[Pre-print, not peer reviewed] Mutations in three main epitopes of the SARS-CoV-2 spike receptor-binding domain (RBD) affect neutralizing activity of convalescent polyclonal serum. Mutations that affect neutralizing activity usually occur at only a few sites and mutations occurring at the E484 site had the largest average effect with a >10 fold reduction in the neutralization…
December 30, 2020
Prior SARS-CoV-2 Infection Is Associated with Protection against Symptomatic Reinfection
In a retrospective cohort study of healthcare workers (HCW) (n=17,126) in the UK, HCW without confirmed SARS-CoV-2 infection (negative PCR and serology) during the first wave experienced higher rates of symptomatic testing and PCR test positivity rates in the second wave 6 months later than HCW with confirmed SARS-CoV-2 infection during the first wave. Only…
December 28, 2020
Antibody Status and Incidence of SARS-CoV-2 Infection in Health Care Workers
The presence of SARS-CoV-2 anti-spike or anti-nucleocapsid IgG antibodies was associated with a reduced risk of SARS-CoV-2 reinfection over 6 months of follow-up among health care workers in the UK (n=12,541). The risk of testing positive for SARS-CoV-2 by PCR during study follow-up was 1.09 per 10,000 person-days at risk among workers who were negative…
December 23, 2020
Antibody Responses 8 Months after Asymptomatic or Mild SARS-CoV-2 Infection
Choe et al. used four commercial immunoassays to measure SARS-CoV-2 antibodies from seven participants with asymptomatic SARS-CoV-2 infection and 51 patients with mildly symptomatic infections eight months after they tested positive by rt-PCR. For three of the four immunoassays used, seropositivity rates were high (69% to 91%). Antibody positivity differed significantly between the immunoassay methods,…
December 16, 2020
Sustained Positivity and Reinfection With SARS-CoV-2 in Children: Does Quarantine/Isolation Period Need Reconsideration in a Pediatric Population?
A retrospective observational study of sustained SARS-CoV-2 RT-PCR positivity in children found that of 989 pediatric patients who had tested positive, 172 had multiple subsequent tests over months, of whom 68 had two or more consecutive positive tests (median interval 14 days), and 27 of those 68 had sustained-positive status (median 26 days). In addition,…
Clinical, Laboratory, and Temporal Predictors of Neutralizing Antibodies to SARS-CoV-2 among COVID-19 Convalescent Plasma Donor Candidates
A study assessing the durability of neutralizing antibody responses (nAb) and factors to streamline plasma donor selection found that nAb titers correlated with COVID-19 severity (aOR=6.59), age (aOR=1.03 per year), and male sex (aOR=2.08). Functional levels declined over time and a small number of individuals (2.8%) who recovered from COVID-19 lacked adaptive immune responses. Of…
December 10, 2020
Long-Term SARS-CoV-2 RNA Shedding and Its Temporal Association to IgG Seropositivity
A retrospective study juxtaposing longitudinal SARS-CoV-2 PCR positivity with IgG antibody seropositivity (n=851) found patients who seroconverted may still actively shed viral RNA. Out of 90 patients with positive IgG results (mean upper bound from initial PCR test = 37.8 days), 14 were actively shedding viral RNA (positive PCR test) between 0 and 64 days…
Previous page Next page