Most Covid-19 patients develop antibodies that appear to remain "stable", according to a new UK analysis.
Researchers at St George’s Medical School, London, found that more than 90% of patients developed antibodies – and that they stayed stable for the length of their two-month long study.
The findings, involving a study of 177 patients, offer little information about long-term immunity to the virus – although they offer hope that it may be gained.
Researchers found that up between 2% and 8.5% of patients did not develop antibodies at all – and tended to be younger than other patients and more likely to be of white ethnicity.
The study linked high antibody response to factors associated with severe illness such as weight, hypertension and non-white ethnicity.
Researcher Professor Sanjeev Krishna said: “Our results provide an improved understanding 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.
“With the number of infections in the UK going down, we now have the very welcome challenge of attempting to carry out more tests to understand whether other factors are associated with an immune response, such as viral load and genetic factors. We hope that by sharing our data at an early stage, this will accelerate progress towards effective use of test results around the world.”
* Testing and contract tracing might need to be kept going for two years to protect lives from the virus and keep the economy going, according to a new analysis.
There should also be widespread use of face-coverings and isolation of contacts of infected people, according to the research by Edinburgh University and University College London, UK, and the University of Haifa, Israel.
In the UK this would keep deaths down to 52,000 – just 10,000 more than present – and preventing another 50,000, the researchers say. The study used mathematical and economic models.
Researcher Dr Tim Colbourn, from UCL, said: “Our results make a strong case for expanding testing and tracing immediately to control COVID-19 spread until a vaccine or highly effective drugs are available.
“By clearly showing the health and economic benefits that such a system could lead to, we hope our study will help to galvanise support for integrated testing, tracing and isolation for the UK.”
Worldwide the total number of reported deaths reached 439,000 yesterday, with more than a quarter of them reported in the USA. India reported more than 10,000 new cases and 395 deaths – and Brazil 23,000 new cases and 729 deaths.
Dynamics of IgG seroconversion and pathophysiology of COVID-19 infections medRxiv 9 June 2020
https://www.medrxiv.org/content/10.1101/2020.06.07.20124636v2
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