“From the memory of a toxicologist, I had never seen this. Some colleagues even thought it was a typing error”, exclaims Professor Robert Barouki, director of research at the National Institute of health and medical research (Inserm) and professor at Paris-Descartes University. The object of the astonishment of this specialist in the links between pollution and health? The new limit values concerning the exposure of the population to bisphenol A (BPA), proposed in December by the European Food Safety Agency (Efsa). “It plans to reduce this threshold by 100,000 times. All Europeans will find themselves above it: this will put major pressure on the total banning of this pollutant”, explains the scientist.
Bisphenol A had already been the subject of EFSA regulations in 2015, applied differently depending on the state, some banning this molecule in baby bottles, others in all products in contact with food. At the time, specialists were mainly concerned about the consequences of this molecule on the brain, metabolism and the reproductive system.
“The previous limit was however provisional, pending further studies. It was the data concerning its impact on the immune system that led our experts to issue this opinion,” said a spokesperson for the European agency. BPA would increase the quantities of certain lymphocytes involved in various immune diseases, including allergies, asthma and autoimmune disorders. The final opinion of Efsa must be delivered at the end of the year, its experts must now answer the questions raised during the public consultation phase, which ended on February 22.
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Fewer antibodies in exposed children
The effect of pollutants on immunity is not a discovery. Heavy metals or benzene, among others, are known to overstimulate our immune system. Conversely, some products can be immunosuppressive: they will reduce the effectiveness of our defences. This is particularly the case for dioxins and polychlorinated biphenyls (PCBs), which are already subject to prohibition and control measures. More recently, scientists have also realized that a very widespread family of molecules, perfluorinated compounds, could potentially have the same effect – even making the most exposed people more vulnerable to viruses like Covid-19. .
Unknown to the general public, these “PFAS”, for per- and polyfluoroalkyl substances, have been used for decades for their waterproofing and insulating properties. We find them in our clothes and our rain shoes, our non-stick pans and even in food packaging or cosmetics. Their consequences on health are already well documented – cancers of the testicles or kidneys, elevated cholesterol levels, liver problems… It is a Danish researcher with a very French name, Philippe Grandjean, associate professor at Harvard University in United States, which was the first to show their consequences on immunity.
In 2008, it tested 600 children from the Faroe Islands for whom umbilical cord blood samples had been stored. He then discovered that the more their mothers had been exposed to PFAS, the less the children, despite being vaccinated, had antibodies against tetanus and diphtheria at the age of 5 years. “This method is recommended by the World Health Organization to assess the immunotoxicity of a molecule. Since then, similar results have been found in other countries, for different vaccines, as well as in adults”, recalls the scientist.
Continuing his work in Denmark, he also showed that the greater the in utero exposure to PFAS, the greater the risk of children being subsequently hospitalized for infectious diseases, particularly pulmonary. Work has also since been confirmed in other countries.
Products widely distributed in the environment
Philippe Grandjean therefore naturally wondered about the effect of these compounds in people infected with Covid. For this, he had a major asset: the Danish bio-bank, where the Copenhagen authorities keep the “tube bottoms” of blood samples from hospitalized citizens. “We studied 320 subjects infected with Covid and we showed a correlation between the severity of their disease and the level of a perfluorinated compound in their blood, PFBA”, describes the scientist. This molecule, which belongs to the PFAS family, is supposed to be less toxic than others, but it has the particularity of accumulating in the lungs…
“At least three other articles, which have since appeared, show similar results. It’s still a few, but we already knew, in animal models, that PFAS increased susceptibility to infection by different viruses, including influenza. Why? would it be different with this coronavirus?”, indicated to L’Express, in an interview published on December 17, Professor Linda Birnbaum, director until 2019 of the American Institute of Environmental Health Sciences.
Other studies are underway, including in France, to assess the consequences of impregnation with PFAS on anti-Covid vaccination. “We want to take advantage of the Covicompare trial, conducted under the aegis of Inserm, to study in great detail the effect of perfluorides on the immunity of the elderly”, explains Professor Barouki.
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A question that should remain relevant for a long time to come: if some PFAS are banned or supervised in Europe, these products are widely distributed in the environment. Almost impossible to destroy, they will continue to contaminate us through polluted water or food.
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