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Tag: antibodies
April 15, 2021
SARS-CoV-2 Antibody Response in Persons with Past Natural Infection
Vaccine-elicited neutralizing antibody geometric mean titers (GMT) among healthcare workers who received the first dose of the Pfizer-BioNTech vaccine 1-2 months, 2-3 months, and more than 3 months after a prior SARS-CoV-2 infection were 437, 559, and 694 arbitrary units/mL, respectively. In contrast, healthcare workers with no prior infection had a GMT of 118 units/mL…
April 13, 2021
SARS-CoV-2–Specific Antibodies in Breast Milk After COVID-19 Vaccination of Breastfeeding Women
Vaccine-induced SARS-CoV-2-specific antibodies were found in a high proportion of breastmilk samples obtained up to 6 weeks post-vaccination from breastfeeding women in a cohort study in Israel (n=84,504 total samples). IgA antibody positivity peaked at 86% of samples at week 4 (1 week after second dose) and remained at 66% by week 6. IgG antibody…
Rapid Decline of Neutralizing Antibodies Is Associated with Decay of IgM in Adults Recovered from Mild COVID-19 Disease
SARS-CoV-2-specific IgG antibody levels were relatively stable for up to 6 months, whereas neutralizing antibody responses waned during that time, according to a cohort study of 34 adults with mild COVID-19. By 6 months, only 70% (23 of 33) of participants exhibited a neutralizing response compared to 91% or higher for IgG antibody responses. Presence…
SARS-CoV-2 Infection Rates of Antibody-Positive Compared with Antibody-Negative Health-Care Workers in England: A Large, Multicentre, Prospective Cohort Study (SIREN)
Prior SARS-CoV-2 infection was associated with an 84% lower risk of new infection according to the SIREN Study, a large multi-center prospective study conducted in the UK from June to December 2020. During the study period, 155 potential reinfections were detected among 8,278 participants positive at baseline compared to 1,704 new PCR positive infections detected…
A Public Health Antibody Screening Indicates a Marked Increase of SARS-CoV-2 Exposure Rate in Children during the Second Wave
SARS-CoV-2 seroprevalence among children aged 1-10 years in Bavaria, Germany increased from 0.68% during the first wave (January-August 2020) to 3.92% during the second wave (September-February 2021). The authors suggest that the increase in seropositivity was likely caused by generally higher virus exposure during fall and winter, school openings, and the introduction of variants. By…
April 12, 2021
Antibody Responses in Elderly Residential Care Persons Following COVID-19 MRNA Vaccination
[Pre-print, not peer-reviewed] While all fully vaccinated long-term care residents (n = 70) in a cross-sectional study in the Pittsburg region between March 15 and April 1, 2021 had detectable SARS-CoV-2 antibodies, levels tended to be lower among those who were male, older, used steroid medications, or had a longer length of time since vaccination….
Neutralization of SARS-CoV-2 Variants by Convalescent and Vaccinated Serum
[Pre-print, not peer-reviewed] Sera from convalescent individuals (n = 44) and individuals who received the Pfizer-BioNTech vaccine (n = 51) showed reduced neutralization activity against the SARS-CoV-2 B.1.1.7 and B.1.351 variants. Among vaccinated individuals, the geometric mean 50% receptor binding domain (RBD) antibody concentration was 1.3-fold lower for the B.1.1.7 variant and 1.4-fold lower for…
April 5, 2021
Persistence of Anti-SARS-CoV-2 Antibodies Depends on the Analytical Kit: A Report for Up to 10 Months after Infection
A study of hospitalized and non-hospitalized symptomatic patients (n = 210 samples, 84 patients) over a period of 10 months using six different commercial assays for antibody detection found that assays targeting total antibodies presented higher positivity rates and reached the highest positivity rates sooner than assays directed against IgG alone. The inter-assay agreement was…
April 1, 2021
Longitudinal Dynamics of Antibody Responses in Recovered COVID-19 Patients
SARS-CoV-2-specific IgG antibody titers gradually increased with neutralizing antibody titers while IgM titers more quickly waned in a study of the antibody response dynamics in 24 COVID-19 recovered patients followed up to 42 weeks. While IgG titers were higher among severe than among mild cases, titers did not decline significantly over time in either group….
March 30, 2021
Dynamics of SARS-CoV-2 Neutralising Antibody Responses and Duration of Immunity: A Longitudinal Study
Five distinct patterns of SARS-CoV-2 neutralizing antibody dynamics were found in a longitudinal study of 164 SARS-CoV-2-infected patients in Singapore with follow-up of up to 180 days post-symptom onset. The different dynamics were defined by the trajectory by which antibody levels waned or evolved. Persistent dynamics, observed in the largest group of patients (32%), was…
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