New Highly Sensitive Blood Test Accurately Measures Immunity Against SARS-CoV-2

A team of researchers have developed a new test that is sensitive enough to measure the amount of SARS-CoV-2 neutralizing antibodies present in the bloodstream.

The discovery by scientists at the Lausanne University Hospital (CHUV; Lausanne, Switzerland) and EPFL (École polytechnique fédérale de Lausanne; Switzerland) opens up promising new avenues for tracking immunity acquired by infection or vaccination. With this test, experts can measure the level of protection against variants of the virus and monitor their prevalence over time.

Blood tests detect the presence of antibodies against an infectious agent, such as SARS-CoV-2, in a patient’s bloodstream. Some antibodies simply indicate whether the individual has been previously exposed to either the virus or a vaccine, while others – known as neutralizing antibodies – provide immunity against infection or re-infection. In the case of SARS-CoV-2, neutralizing antibodies work by interfering with the virus’ spike protein, which is the key that the virus uses to enter respiratory system cells by binding to the ACE2 receptors on the cells’ surface.

The new antibody test is a highly sensitive and extremely accurate way of measuring how well a sample of blood serum can prevent the spike protein in its trimeric form – as found on the surface of the SARS-CoV-2 virus – from binding to ACE2 receptors. It completes the diagnostic arsenal in development at EPFL, which also includes the microchip device presented two months ago. Because the new method requires a simple blood test, it can be deployed easily on a large scale. The test results show whether a patient has developed immunity against one or more variants of SARS-CoV-2.

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Lausanne University Hospital
EPFL