Source: COVID-19 Antibodies  Jun 15, 2020  2 years ago
COVID-19 Antibodies Immune Response Could Remain Stable For About Two Months After Diagnosis
COVID-19 Antibodies Immune Response Could Remain Stable For About Two Months After Diagnosis
Source: COVID-19 Antibodies  Jun 15, 2020  2 years ago
COVID-19 Antibodies: Emerging results from an antibody testing research show that COVID-19 antibodies remain stable in the blood of the majority of infected patients almost two months after diagnosis and possibly longer. However the antibodies were not detectable in everyone exposed to the SARS-CoV-2 corona virus, opening discussions on how best to interpret antibody and viral tests.

The study findings give answers to questions around how long people may remain immune after exposure to COVID-19 and provide insight into how different age and ethnic groups respond to infection.
The research, led by researchers and clinicians at St George's, University of London and St George's University Hospitals NHS Foundation Trust in collaboration with colleagues at the Liverpool School of Tropical Medicine, Mologic Ltd. and Institut Pasteur de Dakar, Sénégal, is an analysis of antibody test results from 177 individuals diagnosed with COVID-19 infection from a PCR nucleic acid test. The work is funded by a DFID/Wellcome Trust Epidemic Preparedness coronavirus grant.
The research findings were published on the pre-print server medRxiv, and is yet to have been peer-reviewed.
The research measured the levels of COVID-19 antibodies in patients exposed to the coronavirus. The results demonstrate that in those patients with an antibody response, the levels remained stable for the duration of the study (almost two months). The study also shows that those patients with the most severe infections having the largest inflammatory response were more likely to develop antibodies.
The study team suggest that this may be due to antibody responses working in parallel with an inflammatory response to severe disease, or that a higher viral load could lead to greater stimulation of the inflammatory and antibody development pathways. Further mechanistic work is required to understand if and why this may be the case.
However between 2 and 8.5% of patients did not develop COVID-19 antibodies at all. The researchers indicate this may be because the immune response in these patients could be through other immune response mechanisms, such as different antigens or T-cells. Another option could be that relatively mild infections may be restricted to particular locations in the body, such as within mucosal cells of the respiratory tract, where antibody responses are instead dominated by a secretory immune system.
The research also explored associations between different characteristics and antibody responses. Being of non-white ethnicity was associated with a higher antibody response, tying into the knowledge that patients from BAME backgrounds are more likely to develop severe disease. Older patients and those with other conditions, such as with hypertension and being overweight were also more likely to have an antibody response.
Dr Sanjeev Krishna, Professor and corresponding author on the paper from St George's, University of London, told Thailand Medical News,  "Our study results provide an improved understa nding of how best to use viral and antibody tests for coronavirus, especially when not every person exposed to the virus will have a positive response. We need to understand how best to interpret the results from these tests to control the spread of the virus, as well as identifying those who may be immune to the disease.
Dr Krishna further added, "It is important to carry out more tests to understand whether other factors are associated with an immune response, such as viral load and genetic factors. The team hopes that by sharing the research data at an early stage, it will accelerate progress towards effective use of test results around the world."
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Feb 05, 2020  2 years ago
Source : Thailand Medical news