In the current state of knowledge, according to the established formula, the High Authority for Health (HAS) has dampened the hopes of those who relied heavily on serological tests to know whether or not we were protected from Covid-19. Recall that this type of biological examination, carried out by blood test, allows us to say whether or not we have developed “antibodies” after having crossed the virus. Which, eventually, would guarantee immunity. A principle commonly accepted in medicine, but which is far from being proven for the moment for this coronavirus.
"Faced with the lack of knowledge on immunity developed by people who have had Covid-19, the High Authority for Health recommends to remain cautious in the use of serological tests", writes this body of independent medical experts, in its opinion given this Saturday. The HAS was contacted by the government to decide on the place to be given to these serological tests in the medical strategy to be implemented. Knowing that there are already other virological tests, performed by nasal swab, called "RT-PCR" which allow to know if one is carrying the virus, when one has symptoms.
"No certainty" with serological tests
During a press point, the president of the HAS, Professor Dominique Le Guludec, clarified why in the state serological tests could not benefit from a favorable opinion: "We do not yet know well enough what is our immune response to SARS-Cov2 (NDLR : the other scientific name for the new coronavirus ), and the level of protection it gives us. Serological tests, which provide information on the production of antibodies, do not allow us to know, as it stands, whether we are protected against the virus. "
Faced with this uncertainty, the HAS "excludes screening in the general population with serological tests". And Professor Dominique Le Guludec added: “These serological tests cannot allow the establishment of an immunity passport for purposes of deconfinement. Am I protected? To this fundamental question, today, serological tests do not give us certainties. "
"Let us think above all about respecting barrier gestures"
Are they therefore useless? No, answers the HAS, but it only assigns them a minor role in the screening strategy. “Their use can be recommended, in certain cases, in addition to virological tests, to measure the circulation of the virus. So they are useful in refining a diagnosis, but are absolutely not the alpha and omega of the test response.
However, the HAS specifies that its opinion reflects the state of science today and that the evolution of knowledge is always likely to evolve. The opinion, which relates to Elisa tests used in medical biology laboratories, should be followed in the coming days by a new opinion on individual serological tests. "Above all, let's think about respecting barrier gestures," said Professor Le Guludec.
The French National Authority for Health also specifies that these serological tests must not be used outside the strictly medical field. “Uses for collective purposes, such as the organization of work within the company, or assistance with deconfinement, are not possible. "