A new serological test makes it possible to determine in an individual the level of antibodies produced to neutralize Covid-19 and its variants.
- A rapid serological test makes it possible to see if an individual has antibodies neutralizing Covid-19 and its variants.
- This test makes it possible to evaluate the immune response of an individual who has been infected or vaccinated.
A small drop of blood is enough to give the answer: does an individual have enough antibodies neutralizing Covid-19 and its variants? Researchers have just developed a new serological test capable of rapidly assessing the level of immune response – and therefore protection – of a person after an infection or vaccination. Their results were published in review Science Translational Medicine.
The major advance of this test is to measure the so-called neutralizing antibodies, that is to say those present on the spike protein by which the virus or its variants enters a cell. If present in the body, these antibodies protect the individual by preventing the virus or its variants from reaching the cells.
A test to assess the protection of the vaccine against Covid-19…
This new serological test is very fast. Individuals prick their finger to release a small drop of blood. This is placed in a tube and a maximum of three hours later the result comes in: the individual knows if he has antibodies neutralizing SARS-CoV-2 and all its known variants. Before, it was possible to obtain this information, but it required a procedure of several days in the laboratory. Now, this new serological test can be performed quickly on thousands of people a day and at a lower cost.
“This test helps determine what level of protective immunity is triggered either by infection or vaccination, Explain Didier Trono virologist, who participated in the development of this test, in the newspaper Le Temps. This allowed us to observe, for example, that people infected without showing many symptoms generally have levels of neutralizing antibodies which are quite low, and which often do not work against the new variants.”.
In the long term, this test will therefore make it possible to better assess the protection of the vaccine for the variants. Laboratories could also obtain information from it to better adapt the vaccine – during its manufacture – or determine a recall period so that the level of neutralizing antibodies remains stable. The researchers envisage the use of this test for both the general public and for healthcare establishments. But, for the moment, it is only available on medical prescription.
…but also and above all against variants
For several days, the Delta variant has become the majority in France. According to the latest figures published by Santé Publique France on July 12, the Delta variant was present in 62.4% of the tests carried out. To curb its spread, the President of the Republic, Emmanuel Macron, announced the extension of the health pass to activities such as the restaurant, the train, the plane or the theater, the end of free PCR and antigenic tests from next fall and compulsory vaccination of caregivers.
Currently, nearly 36 million people have received at least one dose of the Covid-19 vaccine, including 27 million who are fully vaccinated. This new serological test could make it possible to assess the effectiveness of the vaccine on the Delta variant and, if the results are good, perhaps encourage more French people to take their first dose.
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