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Tag: immunity
October 7, 2020
Antibody Reactivity to SARS-CoV-2 in Adults from the Vancouver Metropolitan Area Canada
[Pre-print, not peer-reviewed] A substantial proportion of individuals who lacked serological evidence of SARS-CoV-2 exposure showed antibody reactivity against SARS-CoV-2 antigens, possibly due to cross-reactivity of antibodies against other coronaviruses. Among 276 adults tested for SARS-CoV-2 antibodies during the second wave of the COVID-19 pandemic in Vancouver, Canada (May 17-June 19, 2020), 3 participants tested…
October 2, 2020
Waning of SARS-CoV-2 RBD Antibodies in Longitudinal Convalescent Plasma Samples within Four Months after Symptom Onset
A decrease in anti-RBD antibodies was observed over time in a study of individuals who had recovered from SARS-CoV-2 and who gave repeated blood donations. The study determined that the decline was not due to repeated donations, but rather that the anti-RBD response wanes over time of convalescence. The response was found to be relatively…
October 1, 2020
Recent Endemic Coronavirus Infection Is Associated with Less Severe COVID-19
Pre-existing immune responses against endemic human coronaviruses (eCoVs), which are etiologic agents for the “common cold” that share extensive sequence homology with SARS-CoV-2, may mitigate disease manifestations from SARS-CoV-2 infection. A study among 252 patients with a COVID-19 related hospitalization reported lower risk of ICU admission (OR=0.1) and death (HR=0.3) among patients with eCoV antibodies…
September 29, 2020
COVID-19 Seroprevalence Surveys and Antibody Decline – A Note of Caution on Antibody Decline
[Pre-print, not peer-reviewed] Despite ongoing COVID-19 activity in Ontario, the prevalence of anti-SARS-CoV-2 antibodies did not change substantially (range 0.4% – 1.4% positive) between five surveys conducted from March to August 2020. Bolotin et al. analyzed residual clinical specimens and found that the geometric mean concentration of antibodies among the positive samples declined between June…
September 22, 2020
Kinetics of SARS-CoV-2 Specific Antibodies (IgM, IgA, IgG) in Non-Hospitalized Patients Four Months Following Infection
Levels of antibodies against SARS-CoV-2 were found to decline over an 18-week period following symptom onset, although antibodies remained detectable. Data from longitudinal profiles of different antibody immunoglobulin classes using tests with different antigens and neutralizing titers showed that receptor-binding-domain-specific (RBD) and nucleocapsid protein-specific (NCP) IgM as well as S1-specific IgA levels significantly decreased within…
COVID-19 Herd Immunity in the Brazilian Amazon
[Pre-print, not peer-reviewed] Between 44% and 66% of the population of Manaus, Brazil was infected with SARS-CoV-2 through the course of the epidemic, as estimated by a study of cross-sectional monthly seroprevalence estimates in blood donors. According to Buss et al., although nonpharmaceutical interventions and other changes in population behavior may have helped to limit…
September 17, 2020
Change in Antibodies to SARS-CoV-2 Over 60 Days Among Health Care Personnel in Nashville, Tennessee
Anti-SARS-CoV-2 antibody levels declined over 60 days among all 19 health care personnel in Tennessee who had anti–SARS-CoV-2 antibodies at baseline. In 11 (58%), antibody levels declined substantially enough that they tested negative at 60 days, while 8 (42%) remained seropositive after 60 days. The authors conclude that cross-sectional seroprevalence studies may underestimate rates of…
September 10, 2020
High Seroprevalence of Anti-SARS-CoV-2 Antibodies in Chelsea, Massachusetts
• Among asymptomatic residents of Chelsea, Massachusetts without a prior positive PCR test for SARS-CoV-2 (n=200), the seroprevalence of SARS-CoV-2 antibodies was 32% (18% IgM+IgG+, 9% IgM+IgG-, and 5% IgM-IgG+), representing a substantial burden of undocumented infection. Additionally, 51% of participants reported no symptoms in the preceding 4 weeks, of whom 25% (25/101) were seropositive, and…
September 3, 2020
Disease Severity Dictates SARS-CoV-2-Specific Neutralizing Antibody Responses in COVID-19
Greater disease severity was associated with higher levels of serum neutralizing capacity among 59 patients recovered from COVID-19 in China. Generation of antibodies capable of completely neutralizing pseudovirus was observed in 80% of patients who recovered from severe illness, while asymptomatic patients failed to generate competent neutralizing antibodies. Complete neutralization was observed in 47% of…
September 2, 2020
Serological Identification of SARS-CoV-2 Infections among Children Visiting a Hospital during the Initial Seattle Outbreak
Six of eight children who had SARS-CoV-2 antibodies detected in leftover clinical samples had not been suspected of having COVID-19. Dingens et al. screened 1,775 leftover serum samples from children seeking medical care at Seattle Children’s Hospital during the early Seattle outbreak period and found one child was seropositive with SARS-CoV-2 in March and seven…
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