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Tag: variants
May 17, 2021
Anti-SARS-CoV-2 Antibodies Persist for up to 13 Months and Reduce Risk of Reinfection
[Pre-print, not peer-reviewed] A longitudinal study of antibody responses among healthcare workers in France, 916 of whom had not had COVID-19 and 393 who were convalescent, found that almost all convalescent individuals (96%) had persistence of anti-S IgG antibodies one year after infection. From month 1 until months 7-9 after infection, SARS-CoV-2 antibodies decreased, with…
May 13, 2021
Quantifying the Potential for Dominant Spread of SARS-CoV-2 Variant B.1.351 in the United States
[Pre-print, not peer-reviewed] An age-stratified SARS-CoV-2 transmission model calibrated to the US population and current vaccination rates suggests that the SARS-CoV-2 B.1.1.7 variant would likely remain the dominant variant of concern in the US compared to the B.1.351 variant through December 2021, if the B.1.351 variant reduced vaccine efficacy by less than 30% or if…
mRNA Vaccine-Induced SARS-CoV-2-Specific T Cells Recognize B.1.1.7 and B.1.351 Variants but Differ in Longevity and Homing Properties Depending on Prior Infection Status
[Pre-print, not peer-reviewed] CD4+ T cell responses elicited by COVID-19 mRNA vaccines respond similarly to spike protein epitopes derived from the SARS-CoV-2 B.1.1.7 and B.1.351 variants of concern and the ancestral strain, based on an analysis of 24 specimens obtained at 3 different timepoints from 8 fully vaccinated individuals. The second vaccine dose appeared to…
May 12, 2021
SARS-CoV-2 Infectivity by Viral Load, S Gene Variants and Demographic Factors and the Utility of Lateral Flow Devices to Prevent Transmission
SARS-CoV-2 index cases with lower PCR cycle threshold (Ct) values (suggesting a higher viral load) tended to have a higher proportion of contacts infected with SARS-CoV2, according to a study combining testing and contact tracing data from England between September 2020 and February 2021. Attack rates were 12% for index cases with Ct=15 and 5%…
May 10, 2021
Vaccination Boosts Naturally Enhanced Neutralizing Breadth to SARS-CoV-2 One Year after Infection
[Pre-print, not peer-reviewed] Among 63 COVID-19 convalescent individuals assessed at 1.3, 6.2 and 12 months after infection, antibody reactivity to the receptor binding domain (RBD), neutralizing activity, and the number of RBD-specific memory B cells remained relatively stable from 6 to 12 months in those who had not been vaccinated. Among the 41% of the…
Precision Health Diagnostic and Surveillance Network Uses S Gene Target Failure (SGTF) Combined with Sequencing Technologies to Identify Emerging SARS-CoV-2 Variants
[Pre-print, not peer-reviewed] A genomic surveillance algorithm developed to combine RT-PCR and sequencing technologies to identify SARS-CoV-2 variants of concern found the frequency of S Gene Target Failure (SGTF) exponentially to 47% and 48% by the last week of March 2021, in both Puerto Rico and US laboratories, respectively. SGTF is used as a proxy…
May 7, 2021
Preliminary Analysis of Safety and Immunogenicity of a SARS-CoV-2 Variant Vaccine Booster
[Pre-print, not peer-reviewed] Preliminary results from a clinical trial (N=80) of a modified Moderna mRNA COVID-19 vaccine administered as a booster 6 months after the two-dose vaccine series induced increases in antibody neutralization titers to the wild type and variant strains B.1.351 and P.1. The authors note that these results demonstrate the ability of a…
May 6, 2021
Effectiveness of the BNT162b2 Covid-19 Vaccine against the B.1.1.7 and B.1.351 Variants
The Pfizer-BioNTech vaccine was 90% effective against PCR-confirmed infection with the SARS-CoV-2 variant B.1.1.7 and 75% effective against the B.1351 variant 14 days after the second dose, according to a nationwide case-control analysis in Qatar through March 2021. Individuals with positive and negative PCR tests were matched on demographics and reason for PCR testing to…
May 5, 2021
Rapid Emergence and Epidemiologic Characteristics of the SARS-CoV-2 B.1.526 Variant — New York City, New York, January 1–April 5, 2021
The SARS-CoV-2 B.1.526 variant, a variant of concern/interest (VOC/VOI) first described in New York City (NYC), does not appear to lead to more severe disease, increased risk of infection after vaccination, or increased risk of reinfection according to preliminary analyses of infections with sequenced virus matched to epidemiologic characteristics in NYC from January to April…
Identification of and Surveillance for the SARS-CoV-2 Variants B.1.427 and B.1.429 — Colorado, January–March 2021
The SARS-CoV-2 B.1.427/B.1.429 variant (aka CAL.20C), a variant of concern/interest (VOC/VOI) first described in California, was first detected in Colorado in late January 2021, and increased from 3-4% of all sequenced infections in late January to 20-22% in early March. Cases were dispersed across nearly half of counties. Among 60 cases who completed enhanced interviews,…
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