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Tag: immunity
May 18, 2021
Decay of Fc-Dependent Antibody Functions after Mild to Moderate COVID-19
Antibody effector functions associated with opsonization and killing of infected cells declined over time in a cohort of 58 subjects recovering from mild-to-moderate COVID-19. Levels of anti-SARS-CoV-2 spike (S) antibodies with Fcy receptors, S-specific antibody-dependent cellular cytotoxicity (ADCC), and antibody dependent phagocytosis (ADP) declined from the initial peak in samples drawn ~30-60 days post-symptom onset…
May 17, 2021
Risk of SARS-CoV-2 Reinfection in a University Student Population
The risk of SARS-CoV-2 reinfection among college students with prior infection was 2.2% (n = 16,101, 2,021 with and 14,080 without previous infection), while estimated protection from previous infection was 84% among students tested in fall 2020 and spring 2021 semesters at a large university in South Carolina. All students with access to main campus…
Anti-SARS-CoV-2 Antibodies Persist for up to 13 Months and Reduce Risk of Reinfection
[Pre-print, not peer-reviewed] A longitudinal study of antibody responses among healthcare workers in France, 916 of whom had not had COVID-19 and 393 who were convalescent, found that almost all convalescent individuals (96%) had persistence of anti-S IgG antibodies one year after infection. From month 1 until months 7-9 after infection, SARS-CoV-2 antibodies decreased, with…
May 13, 2021
Persistence of Antibody and Cellular Immune Responses in COVID-19 Patients over Nine Months after Infection
Anti-SARS-CoV-2 IgG, IgM, and neutralizing antibodies against the spike and nucleocapsid proteins were detected in approximately 90% of participants in a cross-sectional study of 59 mostly mild COVID-19 patients after a median of 317 days (range 257 – 343) since symptom onset, while roughly 60% of patients had anti-receptor binding domain (RBD) IgG antibodies. In…
Heterogeneous Magnitude of Immunological Memory to SARS-CoV-2 in Recovered Individuals
SARS-CoV-2-specific cellular and humoral immune responses were maintained up to 5 months post infection in a cohort of professional soccer players in Italy (n=30). 20% of participants displayed weaker immune responses over time, indicating heterogeneity in magnitude of immunological memory. Stronger cellular immune response was associated with symptomatic infection as indicated by higher levels of…
May 12, 2021
Passive and Active Immunity in Infants Born to Mothers with SARS-CoV-2 Infection during Pregnancy: Prospective Cohort Study
[Pre-print, not peer-reviewed] In a cohort of US mothers testing positive for SARS-CoV-2 during pregnancy (n=145), anti-SARS-CoV-2 antibodies were detected in 65% and 58% of maternal and cord blood samples at delivery, respectively. The IgG transplacental transfer ratio was significantly higher among women receiving their first maternal positive PCR test 60-180 days before delivery compared…
Antibody Responses After a Single Dose of ChAdOx1 NCoV-19 Vaccine in Healthcare Workers Previously Infected with SARS-CoV-2
[Pre-print, not peer-reviewed] Sera of participants with detectable spike antibodies produced by natural infection had higher levels of anti-SARS-CoV-2 spike IgG antibodies against the wild-type strain and variants of concern (B.1.1.7, B.1351, and P.1) at least one week after a single dose of the Oxford-Astrazeneca vaccine (n=83) compared to sera from a mixed group of…
Cross-Sectional Serosurvey of Companion Animals Housed with SARS-CoV-2-Infected Owners, Italy
Anti-SARS-CoV-2 nucleocapsid (N) antibodies were detected in 7% of pets (14 of 198) in a serosurvey conducted in Italy from March to June 2020. All 14 seropositive animals lived with SARS-CoV-2-infected owners. In the households of SARS-CoV-2–infected owners, 20% (11 of 54) of cats and 3% (3 of 93) of dogs were seropositive. The proportion…
May 10, 2021
Vaccination Boosts Naturally Enhanced Neutralizing Breadth to SARS-CoV-2 One Year after Infection
[Pre-print, not peer-reviewed] Among 63 COVID-19 convalescent individuals assessed at 1.3, 6.2 and 12 months after infection, antibody reactivity to the receptor binding domain (RBD), neutralizing activity, and the number of RBD-specific memory B cells remained relatively stable from 6 to 12 months in those who had not been vaccinated. Among the 41% of the…
Progressive and Parallel Decline of Humoral and T Cell Immunity in Convalescent Health Care Workers with Asymptomatic or Mild-Moderate SARS-CoV-2 Infection
Among healthcare workers in Spain who recovered from COVID-19 (n = 22), T-cell response was significantly lower among those with early loss of antibodies (6 cases, 27%) a median of 1.8 months after diagnosis. After 5.1 months, 77% of participants had antibody decline (41% seroreverted; p<0.01), and 36% lost T-cell response (75% lost response to…
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