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Tag: variant
June 15, 2021
SARS-CoV-2 Delta VOC in Scotland: Demographics, Risk of Hospital Admission, and Vaccine Effectiveness
SARS-CoV-2 infections caused by the B.1.617.2 (Delta) variant of concern were at increased risk of hospitalization (HR=1.9) compared to the B.1.1.7 (Alpha) variant after adjusting for demographics, temporal trends, and comorbidities, according to an analysis of 19,543 confirmed infections and 377 hospitalizations in Scotland from April 1 to June 6, 2021. Considering the whole population…
June 14, 2021
The SARS-CoV-2 MRNA Vaccine Breakthrough Infection Phenotype Includes Significant Symptoms, Live Virus Shedding, and Viral Genetic Diversity
A study of 24 breakthrough SARS-CoV-2 infections among fully vaccinated US Military Health System beneficiaries indicated that most infections (67%) occurred among those without comorbid conditions, 57% reported close contact with a COVID-19 case in the past month, and no case of breakthrough infection resulted in hospitalization. Sequencing from 10 of 13 qPCR-positive specimens indicated…
June 9, 2021
Outbreak of SARS-CoV-2 B.1.1.7 Lineage after Vaccination in Long-Term Care Facility, Germany, February-March 2021
A SARS-CoV-2 outbreak in a long-term care facility in Germany resulted in a milder disease course, considerably shorter viral RNA shedding (7.5 vs 31 days), and lower peak viral load in vaccinated residents with breakthrough infection compared to unvaccinated residents. The outbreak involved a sequence-confirmed B.1.1.7 (Alpha) variant and resulted in 16 breakthrough infections in…
June 7, 2021
Neutralising Antibody Activity against SARS-CoV-2 VOCs B.1.617.2 and B.1.351 by BNT162b2 Vaccination
A study of the effectiveness of neutralizing antibody titers (NAbTs) against the B.1.617.2 SARS-CoV-2 variant, first identified in India and now widely circulating in the UK, found that two doses of the Pfizer-BioNTech vaccine elicited anti-wild-type spike antibodies in all participants, while NAbTs were reduced 5.8-fold against B.1.617.2 relative to wild-type, a significantly greater reduction…
Adverse Outcomes Associated with SARS-CoV-2 Variant B.1.351 Infection in Vaccinated Residents of a Long Term Care Home, Ontario, Canada
Over a period of 3 weeks, an outbreak at a long-term care facility in Ontario, Canada likely originating from an unvaccinated staff member infected with the B.1.351 variant sickened 4 staff members (2 fully vaccinated, 1 single dose, one unvaccinated) and 9 fully vaccinated residents. Two unvaccinated staff members had infections due to other variants…
Comparative Household Secondary Attack Rates Associated with B.1.1.7 B.1.351 and P.1 SARS-CoV-2 Variants
[Pre-print, not peer-reviewed] A study conducted in Ontario, Canada found that household secondary attack rates were 20.2% for wild-type, 25.1% for B.1.1.7, 27.2% for B.1.351 or P.1, and 23.3% for non-variants of concern (VOC) mutations in SARS-CoV-2. Cases were grouped into households based on reported residential address: 7,555 (28%) were wild-type, 17,058 (63%) were B.1.1.7,…
May 26, 2021
Single-Dose SARS-CoV-2 Vaccine in a Prospective Cohort of COVID-19 Patients
[Pre-print, not peer-reviewed] A study comparing antibody responses in 155 previously SARS-CoV-2 infected individuals found a single dose of the Pfizer-BioNTech vaccine provided neutralizing antibody titers exceeding those produced following two vaccine doses in 49 previously uninfected healthcare workers. Additionally, pre-vaccination neutralization titers in persons with previous infection were associated with higher neutralization titers after…
Variants of Concern Are Overrepresented among Post-Vaccination Breakthrough Infections of SARS-CoV-2 in Washington State
[Pre-print, not peer-reviewed] All (n = 20) breakthrough infections detected among fully vaccinated University of Washington healthcare workers involved a variant of concern, compared to a background rate of 68% of community cases being caused by a variant of concern across WA state during the same time period (N=5,174). Additionally, variants that have been reported…
Estimating Infectiousness throughout SARS-CoV-2 Infection Course
An analysis of 936,423 SARS-CoV-2 RT-PCR-positive samples from hospitalized and non-hospitalized persons in Germany found that high viral loads (> 109 copies per swab) were found in 8% of subjects, 1/3 of whom were pre-symptomatic, asymptomatic, or mildly symptomatic. The mean number of days from onset of viral shedding to peak viral load was 4.3….
May 24, 2021
Public Health and Health Systems Impacts of SARS-CoV-2 Variants of Concern A Rapid Scoping Review
[Pre-print, not peer-reviewed] A rapid review of the B.1.1.7, B.1.351, and P.1 SARS-CoV-2 variants (n=37 studies and 21 guidance documents) found evidence for potential increased risks of hospitalization and death associated with the B.1.1.7 variant. While six studies in the review found higher mortality risk associated with B.1.1.7, ranging from 15-67%, three found no differences….
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