Result for
Tag: immunity
June 4, 2021
Prevention and Attenuation of COVID-19 by BNT162b2 and mRNA-1273 Vaccines
[Pre-print, not peer-reviewed] A prospective cohort study (N=3,975) of healthcare personnel and other frontline workers estimated the real-world effectiveness of Pfizer-BioNTech and Moderna COVID-19 vaccines and found that the adjusted effectiveness of full vaccination was 92% (95% CI 76-97%) and effectiveness of partial vaccination was 81% (95% CI 64-90%). Additionally, among partially or fully vaccinated…
Humoral and Cellular Immune Response against SARS-CoV-2 Variants Following Heterologous and Homologous ChAdOx1 NCoV-19BNT162b2 Vaccination
[Pre-print, not peer-reviewed] A study of persons who received one dose of the AstraZeneca SARS-CoV-2 vaccine (N=129) found that a heterologous boost with the Pfizer-BioNTech vaccine induced significantly higher frequencies of spike-specific CD4 and CD8 T-cells and neutralizing antibodies compared to receipt of a second dose of AstraZeneca. These neutralizing antibodies were highly effective against…
June 3, 2021
SARS-CoV-2 Infects Syncytiotrophoblast and Activates Inflammatory Responses in the Placenta
[Pre-print, not peer-reviewed] SARS-CoV-2 RNA was detected in 23 placentas (41%) from a cohort of 55 women who had SARS-CoV-2 infection during late pregnancy and had positive PCR results at delivery. Among infected placentas, three had high viral content and were obtained from mothers who presented with severe COVID-19 and had perinatal adverse outcomes. Examination…
June 2, 2021
Mechanistic Modeling of SARS-CoV-2 Immune Memory Variants and Vaccines
[Pre-print, not peer-reviewed] The COVID-19 transmission model Covasim, with updated methods accounting for trajectories in immune response, SARS-CoV-2 variants, and vaccine roll-out, found that neutralizing antibodies (NAbs) correlated strongly with infection blocking. The model suggests Nabs elicited by natural infection may provide more protection than the same level of Nabs elicited by vaccines; however, vaccines…
Emerging SARS-CoV-2 Variants of Concern Evade Humoral Immune Responses from Infection and Vaccination
[Pre-print, not peer-reviewed] Anti-SARS-CoV-2 antibody binding and neutralizing activity in sera of both convalescent individuals who had recovered from infection that occurred prior to the spread of variants of concern (VOC) (n=69) and recipients of the Pfizer-BioNTech vaccine (n=50) were reduced against the B.1.1.7, B.1.351, and P.1 VOC, according to a cohort study. The largest…
Convalescent-Phase Sera and Vaccine-Elicited Antibodies Largely Maintain Neutralizing Titer against Global SARS-CoV-2 Variant Spikes
Sera collected from individuals with SARS-CoV-2 infection prior to April 2020 (n=18) neutralized pseudoviruses with the mutated spike proteins of variants of concern, including B.1.1.7, B.1.351, and B.1.1.248, with only a minor loss in neutralizing activity. Similarly, neutralizing activity among individuals fully vaccinated with the Pfizer-BioNTech vaccine (n=5) were only reduced up to 3-fold by…
June 1, 2021
Assessment of SARS-CoV-2 Reinfection 1 Year After Primary Infection in a Population in Lombardy, Italy
Individuals with known prior SARS-CoV-2 infection had a 93% lower incidence of SARS-CoV-2 infection in the following year, according to a cohort study in Italy from February 2020 to February 2021. During a mean follow-up of 280 days, 5 reinfections occurred in 1,579 patients with a prior positive PCR test (mean interval between infections >230…
SARS-CoV-2 Antibody Kinetics Eight Months from COVID-19 Onset: Persistence of Spike Antibodies but Loss of Neutralizing Antibodies in 24% of Convalescent Plasma Donors
Following infection with SARS-CoV-2, the half-life of SARS-CoV-2 neutralizing antibodies was shorter than the half-life of antibodies directed against spike or nucleocapsid. In a cohort study of 148 individuals followed for a median of 8.3 months, antibodies followed a biphasic decay curve. Neutralizing antibody titers contracted the fastest, with an estimated half-life of 47 days…
Neutralization Heterogeneity of United Kingdom and South-African SARS-CoV-2 Variants in BNT162b2-Vaccinated or Convalescent COVID-19 Healthcare Workers
97% (28 of 29) of healthcare workers with no prior infection had neutralizing activity against the SARS-CoV-2 B.1.351 variant of concern in their sera 1 week after receiving the second dose of the Pfizer-BioNTech vaccine, compared to only 60% (9 of 15) of healthcare workers who had COVID-19 6 months earlier. Geometric mean titers (GMTs)…
Distinct Immunological Signatures Discriminate Severe COVID-19 from Non-SARS-CoV-2-Driven Critical Pneumonia
An analysis of the immune response profile of COVID-19 patients suggests that T-cell exhaustion and impaired early antiviral response are characteristic of severe COVID-19 when compared to other causes of severe pneumonia. The authors enrolled participants with either or mild/moderate (n=86) or severe COVID-19 disease (n=35) and participants with other causes of hospital acquired pneumonia…
Previous page Next page