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Tag: immunity
May 7, 2021
Antibody Response to MRNA SARS-CoV-2 Vaccine among Kidney Transplant Recipients – Prospective Cohort Study
A study of kidney transplant recipients who received the Pfizer-BioNTech vaccine (N=308) found that only 36% tested positive for anti-SARS-CoV-2 antibodies 2-4 weeks after receiving the second dose. Factors associated with antibody detection included younger age, higher renal function, and reduced immunosuppression. The authors note that although correlation between antibody levels and protection has not…
Delayed Production of Neutralizing Antibodies Correlates with Fatal COVID-19
A study of humoral immune responses among 229 patients with asymptomatic, mild, moderate, and severe COVID-19 found that persons with delayed neutralizing antibody generation had a higher risk of mortality compared to survivors. Investigators collected multiple serum samples from patients during the course of their illness and examined SARS-CoV-2 neutralizing antibodies and IgG levels. Although…
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…
SARS-CoV-2 Outbreak in Immune-Mediated Inflammatory Diseases: The Euro-COVIMID Multicentre Cross-Sectional Study
In a study including 3,028 patients in Europe with immune-mediated inflammatory disease, symptomatic COVID-19 occurred in 4% (n=122) and anti-SARS-CoV-2 antibodies were detected in 5% (n=166) of patients between June and December 2020. Symptomatic COVID-19 was associated with higher concentrations of C-reactive protein (OR=1.2) and higher numbers of disease flares (OR=1.3). Saadoun et al. (Apr 2021)….
Evaluation of Potential COVID-19 Recurrence in Patients with Late Repeat Positive SARS-CoV-2 Testing
Among 23,176 patients with a positive SARS-CoV-2 in Utah between March and July 2020, 4 of 1,301 patients with at least one additional PCR test ≥60 days after the initial positive test were identified to have probable reinfection and 6 additional patients had possible reinfection. Reinfection was assessed using combined clinical and RT-PCR cycle threshold…
May 4, 2021
SARS-CoV-2 antibody-positivity protects against reinfection for at least seven months with 95% efficacy
Incidence of SARS-CoV-2 infection was 95% lower among persons with prior SARS-CoV-2 infection, indicated by seropositivity, in a cohort study in Qatar. In the study, 129 of 43,044 seropositive persons (0.3%) followed for a median of 16 weeks had at least one positive PCR test supported by evidence of reinfection at least 14 days after…
May 3, 2021
Prior SARS-CoV-2 Infection Rescues B and T Cell Responses to Variants after First Vaccine Dose
An analysis of B and T cell responses in healthcare workers who received one dose of the Pfizer-BioNTech vaccine showed that individuals with prior infection had enhanced T cell immunity and neutralizing antibodies effective against the B.1.1.7 and B.1.351 variants, while those without prior infection showed reduced immunity against variants. B.1.1.7 and B.1.351 spike mutations…
April 30, 2021
Previously Infected Vaccinees Broadly Neutralize SARS-CoV-2 Variants
[Pre-print, not peer-reviewed] A small study of sera from patients vaccinated with the Pfizer-BioNTech vaccine (N=30) found similar levels of anti-SARS-CoV-2 spike antibodies in persons with and without previous documentation of SARS-CoV-2 infection. Additionally, post-vaccination sera from previously infected persons demonstrated higher neutralizing activity in in-vitro against B.1.1.7, B.1.351 and P.1 compared to previously uninfected…
April 29, 2021
Maternal Antibody Response, Neutralizing Potency, and Placental Antibody Transfer After Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) Infection
Among maternal blood samples from SARS-CoV-2 positive patients obtained after delivery (n=32), higher median anti-RBD IgG titers were significantly associated with symptomatic (vs. asymptomatic) infection but not with having a PCR-positive test more than 14 days earlier (vs. PCR-positive test within 14 days). Paired cord blood samples also obtained after delivery show that median cord/maternal…
April 28, 2021
Longitudinal Analysis Shows Durable and Broad Immune Memory after SARS-CoV-2 Infection with Persisting Antibody Responses and Memory B and T Cells
[Pre-print, not peer-reviewed] Longitudinal assessment of immune memory response found that SARS-CoV-2 antibodies exhibited an initial rapid decline from peak levels followed by a much slower decrease (“plateau-phase”). Among 254 recovered COVID-19 patients up to 8 months after symptom onset, anti-spike IgG antibodies were estimated to have an initial half-life of 126 days up to…
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