Vaccine adjuvants and macrophagic myofasciitis]

Aluminium-based adjuvants have been used throughout the world since 1926, and their safety profile is such that they have long been the sole adjuvants registered for clinical use. Their safety has nevertheless been questioned in France over the last few years following the demonstration that aluminium could persist for prolonged periods at the injection site, within macrophages gathered around the muscular fibres and forming a microscopic histological lesion called "macrophagic myofasciitis (MMF)". This image has been observed in patients undergoing a deltoid muscular biopsy for diagnostic purposes of various symptoms essentially including muscular pain and fatigue, in association with a large panel of various symptoms and diseases, including those of an autoimmune nature. Studies of the clinical, biological and epidemiological characteristics undertaken to identify a possible association between the MMF histological image and a systematic disease have remained negative. As of today, available evidence indicates that although vaccine aluminium may persist at the site of injection for years ("vaccine tattoo"), this does not reflect the existence of a diffuse inflammatory muscular disease and is not associated with a specific clinical disease. The existence of sampling bias inherent to the complexity of the clinical and pathological diagnoses remains the most likely hypothesis.