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Tag: immunity
February 26, 2021
Seasonal Human Coronavirus Antibodies Are Boosted upon SARS-CoV-2 Infection but Not Associated with Protection
Cross reactive antibodies generated by pre-pandemic human coronavirus (hCoV) infections are common but are not associated with protection against infection or poor clinical outcomes after infection with SARS-CoV-2. Using samples from a pre-pandemic biobank, 4% of pre-pandemic sera contained antibodies that bound the full-length spike from SARS-CoV-2 and 16% of samples contained antibodies capable of…
February 25, 2021
Evidence of Escape of SARS-CoV-2 Variant B.1.351 from Natural and Vaccine Induced Sera
Neutralizing antibody titers were lower in assays against the SARS-CoV-2 B.1.351 variant compared to an early isolate from Wuhan across several sample sources. The geometric mean neutralizing titers were lower by 13.3-fold in convalescent plasma from patients infected during the first wave in the UK (n=34), by 3.1-fold in sera from patients infected with the…
Association of SARS-CoV-2 Seropositive Antibody Test With Risk of Future Infection
In a cohort study of over 3.2 million US patients with a SARS-CoV-2 antibody test result (88% negative), the ratio of seropositive to seronegative patients with a positive SARS-CoV-2 nucleic acid amplification test (NAAT) decreased from 3% within 30 days of the antibody test to 0.1% after at least 90 days following the antibody test….
Suspected Recurrent SARS-CoV-2 Infections Among Residents of a Skilled Nursing Facility During a Second COVID-19 Outbreak — Kentucky, July–November 2020
SARS-CoV-2 reinfection is suspected among residents of a skilled nursing facility in Kentucky, where 5 residents received positive RT-PCR test results in two separate COVID-19 outbreaks separated by 3 months with at least four negative test results for each resident in between the outbreaks. While only 2 of 5 patients had symptomatic infection during the…
February 19, 2021
Clinical and Laboratory Findings in Patients with Potential SARS-CoV-2 Reinfection, May-July 2020
A clinical and laboratory investigation of potential SARS-CoV-2 reinfection reported to CDC by clinicians in the US did not confirm any cases of reinfection within 90 days of the initial infection, supporting current CDC guidance about retesting for people recovered from COVID-19. Among 73 potential reinfection patients with available records, 70% of patients either had…
Assessment of S1, S2 and NCP-Specific IgM, IgA, and IgG Antibody Kinetics in Acute SARS-CoV-2 Infection by a Microarray and Twelve Other Immunoassays
A study examining antibody kinetics of multiple immunoglobulins in patients hospitalized with acute SARS-CoV-2 infection showed that nucleocapsid protein (NCP)-specific IgA and IgG antibodies are detected earlier, while higher spike (S)1-specific IgA antibody levels occur in severely ill patients. The analysis was conducted using a microarray, eleven different commercial immunoassays (ELISA and CLIA), and one…
February 18, 2021
Serum Neutralizing Activity Elicited by MRNA-1273 Vaccine — Preliminary Report
Neutralizing activity of sera from recipients of the 2-dose Moderna vaccine in the phase 1 trial (n=45) were similar against a SARS-CoV-2 pseudovirus bearing the spike protein from the original Wuhan-Hu-1 isolate, the D614G variant, as well as against 20E (EU1), 20A.EU2, N439K-D614G, and mink cluster 5 variants. In contrast, neutralizing titers against the D614G…
FDA-Authorized COVID-19 Vaccines Are Effective per Real-World Evidence Synthesized across a Multi-State Health System
[Pre-print, not peer reviewed] The Moderna and Pfizer vaccines were 89% effective (95% CI: 68-97%) in preventing SARS-CoV-2 infection occurring at least 36 days after the first dose in a 1:1 propensity score matched analysis of over 60,000 individuals in the US between December 2020 to February 2021. Among those subsequently diagnosed with COVID-19, vaccinated…
Neutralizing Activity of BNT162b2-Elicited Serum — Preliminary Report
Neutralizing activity of sera from recipients of the 2-dose Pfizer vaccine (n=15, 20 serum samples) against wild-type SARS-CoV-2 (USA-WA1/2020) engineered with the full set of spike protein mutations of the B.1.351 variant was weaker than the USA-WA1/2020 strain by approximately two-thirds. Using 50% plaque reduction neutralization testing (PRNT50) on sera obtained 2-4 weeks after the…
Circulating SARS-CoV-2 Variants Escape Neutralization by Vaccine-Induced Humoral Immunity
[Pre-print, not peer reviewed] Analysis of neutralizing activity of sera from individuals vaccinated with either 1 or 2 doses of the Moderna or Pfizer vaccines (n=48) against SARS-CoV-2 pseudoviruses bearing spike proteins with the partial or full set of mutations from the B.1.351 variant show up to a 97-fold decrease in neutralization compared to wild-type. …
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