It was one of the major medical controversies of the 2010s: is there a chronic form of Lyme disease? The debate, muted since the Covid years, is reigniting in France following a contested opinion from the French National Authority for Health (HAS).
The HAS, the French body whose opinions aim to guide health policies, published new recommendations at the end of February on the treatment of Lyme borreliosis, a bacterial infection caused by tick bites.
Every year, tens of thousands of French people become infected, and a few hundred end up in hospital. The infection most often results in reddening of the skin around the bite, but can also cause other disorders, particularly neurological ones.
However, while the immediate treatment of the disease is hardly debated – quickly giving antibiotics to patients – the HAS opinion reawakens a controversy that has been largely hidden in recent years: the existence or not of a chronic form.
A significant number of patients actually experience symptoms for months, even years. For a small portion of the medical profession, often supported by patient associations, this is explained by the long-term persistence of the bacteria in the body.
But this position, which has never been supported by solid studies, does not convince the majority of doctors who nevertheless struggle to explain the presence of long-term symptoms.
This antagonism has long hindered patient care. The hypothesis of a long-term presence of the bacteria serves as the basis for therapies of unproven effectiveness, proposing months of antibiotics. But, at the same time, patients report encountering doctors who largely refuse to acknowledge the existence of long-term symptoms.
The HAS's previous opinion dated back to 2018 and had displeased both sides. It acknowledged the existence of persistent symptoms, terms that did not go far enough for proponents of a chronic form, but which were already too assertive for the main scientific societies.
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These, alongside the Academy of Medicine, had published their own recommendations, a rare disavowal for the HAS.
With its new recommendations, this appears to be part of a more peaceful context, while the debate on the subject has lost media visibility.
A leading figure in the defense of the existence of chronic Lyme disease in the 2010s, Professor Christian Perronne was discredited by his positions during the Covid crisis, particularly those of vaccine skeptics.
On the other hand, research into long-term Covid has given more credibility to so-called "post-infectious" symptoms. And it is among these that the HAS now classifies the persistent form of Lyme disease.
In some respects, her new opinion goes further. It insists that persistent symptoms are a "recognized pathology" and requires patients to avoid "medical wandering."
But, in line with the scientific consensus on the subject, it does not speak of a chronic form and only refers to "post-treatment" symptoms. This nuance is important, because it rules out the idea of a long-term presence of the bacteria, favoring hypotheses such as a disruption of the immune system.
"Under these conditions, it is impossible for us to endorse these recommendations," warned the French Federation Against Tick-Borne Diseases (FFMVT), a stronghold of supporters of chronic Lyme disease, in a statement sent to AFP on Thursday.
The FFMVT, which participated in the discussions, says it requested in vain the introduction of a paragraph referring to a "dissensus" on the subject.
She also regrets that the HAS includes psychotherapy in its monitoring recommendations. The subject is sensitive because the associations reject outright the idea of a psychosomatic explanation in certain cases.
This underlying controversy is also compounded by accusations regarding the use of funding dedicated to research into the disease, despite parliamentarians having allocated ten million euros for this purpose at the end of 2023.
According to the FFMVT, Inserm spent most of it on covering its operating costs. Questioned by AFP, the institute disputed this interpretation, stating that the use of the ten million would be spread over several years and denying any "deficit to be covered."
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