Result for
Topic: Vaccines and Immunity
March 17, 2021
Efficacy of the ChAdOx1 NCoV-19 Covid-19 Vaccine against the B.1.351 Variant
Two doses of the Oxford-AstraZeneca (ChAdOx1 nCoV-19) vaccine did not show protection against mild-to-moderate COVID-19 among people infected with the B.1.351 variant in a multicenter randomized trial in South Africa. Mild-to-moderate COVID-19 developed in 23 of 717 placebo recipients (3.2%) and in 19 of 750 vaccine recipients (2.5%), for an efficacy of 21.9%. Among the…
March 16, 2021
Reinfection Rates among Patients Who Previously Tested Positive for COVID-19: A Retrospective Cohort Study
Previous SARS-COV-2 infection was associated with a lower likelihood of subsequent reinfection compared to those without a previous history of infection. These results are based on a cohort study of over 150,000 patients from a multi-hospital system in Ohio and Florida. Among 8,845 initially PCR-positive patients, 1,278 were retested after ≥90 days and 62 (0.4%)…
BNT162b2 MRNA COVID-19 Vaccine Induces Antibodies of Broader Cross-Reactivity than Natural Infection but Recognition of Mutant Viruses Is up to 10-Fold Reduced
[Pre-print, not peer-reviewed] Antibodies induced by the Pfizer-BioNTech vaccine had higher binding capacities (avidity) than antibodies induced by natural infection against the receptor binding domain (RBD) containing mutations representative of circulating SARS-CoV-2 variants of concern (N501Y, K417N, E484K, and a combination of all three). Vaccine-induced sera (n=6) reduced binding against the RBD containing the N501Y…
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[Pre-print, not peer-reviewed] The SARS-CoV-2 P.1 variant, which has caused large outbreaks in Brazil, is less resistant to neutralization from both convalescent serum and vaccine-induced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…
Antibody Response After SARS-CoV-2 Infection and Implications for Immunity
A review of 66 observational studies found that most adults with SARS-CoV-2 infection develop IgM and IgG antibody responses. Among studies measuring IgM antibody responses (n=21 studies), 80% of adults developed responses, peaking at 20 days. Among studies measuring IgG antibody responses (n=24 studies), 95% of adults developed responses, peaking at 25 days and remaining…
Immunogenicity of a Single Dose of SARS-CoV-2 Messenger RNA Vaccine in Solid Organ Transplant Recipients
Solid organ transplant recipients in the US were less likely to develop anti-SARS-CoV-2 antibody responses after receiving a single dose of either the Moderna or Pfizer-BioNTech vaccines. In a prospective convenience sample, only 17% (76 of 436) had detectable antibody responses at a median of 20 days after the first dose. Transplant recipients who were…
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…
COVID-19 Vaccine Second-Dose Completion and Interval Between First and Second Doses Among Vaccinated Persons — United States, December 14, 2020-February 14, 2021
Vaccination data reported to CDC indicate that among people who received the first dose of either the Moderna or Pfizer/BioNTech vaccines as of February 14, 2021, and for whom enough time had elapsed to receive the second dose, 88.0% had completed the series and 8.6% had not received the second dose. Among all people who…
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…
A Rapid Review of COVID-19 Vaccine Prioritization in the U.S. Alignment between Federal Guidance and State Practice
[Pre-print, not peer-reviewed] A study assessing variability in vaccine priority groups between state and federal guidance found that while state plans largely prioritized healthcare workers and residents of long-term care facilities (consistent with federal guidelines), essential workers were often excluded from state priority plans. Of 37 states that included frontline essential workers, 12 assigned them…
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