Result for
Tag: immunity
December 8, 2020
Defining the Features and Duration of Antibody Responses to SARS-CoV-2 Infection Associated with Disease Severity and Outcome
Analysis of 983 longitudinal plasma samples from 254 SARS-CoV-2 infected individuals with varying disease severity show that compared to severely ill patients, outpatients with mild illness had higher titers of IgG antibodies targeting the S1 domain or receptor binding domain (RBD) of the SARS-CoV-2 spike protein than of those targeting the nucleocapsid antigen. Neutralization assays…
SARS-CoV-2 Infection and COVID-19 Severity in Individuals with Prior Seasonal Coronavirus Infection
[Pre-print, not peer reviewed] Similar SARS-CoV-2 infection rates were observed between people with a prior PCR test for seasonal coronavirus that was positive (3.3%) or negative(3.1%) in a retrospective study among individuals with documented PCR testing for seasonal coronavirus and a subsequent PCR result for SARS-CoV-2 (n=2,768). The authors suggest this finding implies that past…
Dynamics and Correlation Among Viral Positivity, Seroconversion, and Disease Severity in COVID-19
Being critically ill was an independent risk factor of longer PCR-confirmed viral positivity in a retrospective study of 2,142 COVID-19 patients in Wuhan, China. The observed median duration of PCR-confirmed viral positivity was 24 days among critically ill patients and 18 days among non-critically ill-patients, with 20% of samples remaining positive after 5 weeks. Seroconversion…
Seroprevalence of SARS-CoV-2 Antibodies in Seattle Washington October 2019-April 2020
[Pre-print, not peer reviewed] Residual clinical samples from 763 Seattle-area adults collected during March 5-April 1, 2020 show a seroprevalence of antibodies to SARS-CoV-2 of 1.2%, which was 11 times greater than the number of confirmed cases in King County as of April 1. The authors note, however, that participant sampling in the study may…
December 7, 2020
A Prospective Study on Rapidly Declining SARS‐CoV‐2 IgG Antibodies Within One to Three Months of Testing IgG Positive: Can It Lead to Potential Reinfections?
A prospective study of IgG antibody concentrations among 201 individuals in India who tested positive for SARS-CoV-2 found that only 28.4% of participants retained IgG antibody responses at 45-65 days follow-up. The authors highlight the need for future studies that use quantitative antibody assays and measure neutralizing antibody to assess risk of reinfection. Nag et…
December 3, 2020
Intrafamilial Exposure to SARS-CoV-2 Associated with Cellular Immune Response without Seroconversion, France
Exposure to SARS-CoV-2 could induce virus-specific T-cell responses without inducing virus-specific antibody responses. In a study including 11 SARS-CoV-2 serodiscordant couples staying in the same household in which 1 of the 2 partners had lab-confirmed and mild symptomatic COVID-19, the index partners who were initially infected displayed SARS-CoV-2-specific antibody and T-cell responses up to 102…
December 2, 2020
High Seroprevalence but Short‐lived Immune Response to SARS‐CoV‐2 Infection in Paris
Serological testing among 1847 active workers in France showed declining antibody responses to SARS‐CoV‐2 4-8 weeks after the first sampling. Overall, 11% of workers were positive for IgG against SARS-CoV-2-specific proteins and 9.5% had evidence of viral neutralization. Among these, 21% were asymptomatic. In sera obtained 4–8 weeks after the first sampling, anti‐N and anti‐S…
December 1, 2020
IgG Seroconversion and Pathophysiology in Severe Acute Respiratory Syndrome Coronavirus 2 Infection
Among 177 SARS-CoV-2 positive individuals from the UK, 15 (9%) did not seroconvert during the entire 60-day follow-up period, suggesting that a minority of infected persons may not develop detectable IgG against SARS-CoV-2. Persons who seroconverted were older compared to those who did not seroconvert (median age 66 vs 41 years) and were more likely…
November 25, 2020
Estimated SARS-CoV-2 Seroprevalence in the US as of September 2020
A repeated cross-sectional study carried out in all 50 US states, the District of Columbia, and Puerto Rico found that although SARS-CoV-2 seroprevalence varied between 1% and 23%, fewer than 10% of people nationally had detectable antibodies. A total of 177,919 samples were obtained during four periods between July 27 and September 24, 2020 from…
Decline in SARS-CoV-2 Antibodies After Mild Infection Among Frontline Health Care Personnel in a Multistate Hospital Network — 12 States, April–August 2020
Among 156 frontline health care personnel who had positive SARS-CoV-2 antibody test results in spring 2020, 146 (94%) experienced a decline in antibody concentrations at repeat testing approximately 60 days later. In addition, 28% had seroreverted (negative antibody test). Individuals with higher initial antibody responses were more likely to have antibodies detected at the follow-up…
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