Result for
Tag: immunity
March 18, 2021
Assessment of Protection against Reinfection with SARS-CoV-2 among 4 Million PCR-Tested Individuals in Denmark in 2020: A Population-Level Observational Study
Individuals with a positive SARS-CoV-2 PCR test during the first surge in Denmark (prior to June 2020) were less likely to get a positive test during the second surge (September to December 2020) compared to individuals with a negative SARS-CoV-2 PCR test during the first surge. In this nationwide cohort study (n=525,339), 72 of 11,068…
March 16, 2021
Antibody Evasion by the Brazilian P.1 Strain of SARS-CoV-2
[Pre-print, not peer-reviewed] The SARS-CoV-2 P.1 variant, which has caused large outbreaks in Brazil, is less resistant to neutralization from both convalescent serum and vaccine-induced serum than the B.1.351 variant originally identified in South Africa, despite containing similar receptor binding domain (RBD) mutations (E484K, K417N/T and N501Y). Similar to the B.1.351 variant, mutations associated with…
March 15, 2021
An Observational Cohort Study on the Incidence of SARS-CoV-2 Infection and B.1.1.7 Variant Infection in Healthcare Workers by Antibody and Vaccination Status
[Pre-print, not peer-reviewed] A longitudinal cohort study of healthcare workers (HCWs) in England showed that both natural infection and vaccination (two doses of Pfizer/BioNTech or Oxford/AstraZeneca vaccine) provided more than 85% protection against symptomatic and asymptomatic SARS-CoV-2 infection, including with the B.1.1.7 variant. No HCWs who had received both doses had symptomatic infection, and incidence…
Age Cohorts Stratified According to Age-Distributions of COVID-19 Morbidity Statistics Identify Uniquely Age-Dependent CD3 + CD8 + T-Cell Lymphocytopenia in COVID-19 Patients without Comorbidities on Admission
SARS-CoV-2 infection was associated with age-dependent reductions in CD8+ T cell count in a retrospective study of 447 individuals stratified by five age-group cohorts spanning ages 2 to 79. CD4+ T cell, B cell, and natural killer cell counts did not differ between age strata. Plasma C-reactive protein concentrations increased with age. Jin et al. (Mar…
March 12, 2021
Estimated Half-Life of SARS-CoV-2 Anti-Spike Antibodies More than Double the Half-Life of Anti-Nucleocapsid Antibodies in Healthcare Workers
Among healthcare-workers (HCWs) (n=118) who had a previous SARS-CoV-2 infection, 92% were still positive for anti-spike (S) antibodies compared to only 18% for IgG anti-nucleocapsid (N) antibodies after 7-10 months. At 1-3 months, 98% of HCWs were positive for anti-S antibodies compared to 85.6% anti-N antibodies. The mean half-life for anti-S antibodies was 19 days…
March 11, 2021
Immune Response to SARS-CoV-2 Variants of Concern in Vaccinated Individuals
[Pre-print, not peer-reviewed] Sera from both individuals with prior SARS-CoV-2 infection (n=35) and individuals fully vaccinated with the Pfizer-BioNTech vaccine (n=23) showed nearly identical antibody binding responses against the B.1.1.7 Cluster 5 and CAL.20C variants compared to wild-type SARS-CoV-2. In contrast, both binding and neutralizing antibody responses among vaccinated individuals were diminished against the B.1.351…
March 10, 2021
Spike Mutations in SARS-CoV-2 Variants Confer Resistance to Antibody Neutralization
[Pre-print, not peer-reviewed] A panel of 28 SARS-CoV-2 pseudoviruses bearing single or combined spike protein mutations found in the 501Y.V1, 501Y.V2, and 501Y.V3 variants tested against a panel of monoclonal antibodies (mAbs) and convalescent patient plasma collected early in the pandemic showed that the 501Y.V2 variant was the most resistant against mAbs and convalescent plasma,…
Previous SARS-CoV-2 Infection Increases B.1.1.7 Cross-Neutralization by Vaccinated Individuals
[Pre-print, not peer-reviewed] Sera from individuals who had been previously infected with SARS-CoV-2 and received the vaccine showed equivalent neutralizing responses against the B.1.1.7 variant and original virus strain, while sera from vaccinated individuals with no prior infection showed reduced neutralization against B.1.1.7. Neutralizing activity was assessed against pseudoviruses bearing the spike protein from the…
SARS-CoV-2 501Y.V2 (B.1.351) Elicits Cross-Reactive Neutralizing Antibodies
[Pre-print, not peer-reviewed] Antibody responses to the 501Y.V2 SARS-CoV-2 variant in a cohort of patients hospitalized with COVID-19 in South Africa (n = 89) were found to be robust and showed high levels of cross-reactivity against the virus strain from the first wave. Furthermore, sera from patients infected with 501Y.V2 also neutralized the 501Y.V3 (P.1)…
March 9, 2021
SARS-CoV-2-Specific T Cell Memory Is Sustained in COVID-19 Convalescents for 8 Months with Successful Development of Stem Cell-like Memory T Cells
[Pre-print, not peer-reviewed] Whole blood analysis from 94 individuals who had been infected with SARS-CoV-2 in South Korea found that, SARS-CoV-2-specific memory T cell responses were maintained at up to 8 months post-symptom onset. Among 30 individuals with longitudinal samples beyond the first month, no significant differences in memory T cell responses were observed between…
Previous page Next page