Influenza vaccine with squalene adjuvant: new preparation. No better than available products.

(1) Injectable influenza vaccines reduce morbidity and mortality in people over 65 years. (2) A new influenza vaccine, with an adjuvant (MF59C.1) based on squalene, is now marketed in France for people over 65, and especially those with chronic conditions at risk of influenza complications. (3) The clinical evaluation dossier contains data from about twenty immunogenicity studies in more than 4000 elderly subjects. According to a meta-analysis of these studies, there is no firm evidence that the MF59C.1 adjuvant vaccine is any better than other vaccines at inducing immunity in elderly people with chronic conditions. (4) A retrospective analysis of mortality among subjects enrolled in immunogenicity studies showed no significant difference between groups receiving the squalene adjuvant vaccine and groups receiving another influenza vaccine, either in the general population or in subsets of patients with relevant chronic conditions. (5) Local adverse effects (pain, rash, induration) and systemic adverse effects (malaise, myalgia, headache) were significantly more common after the squalene adjuvant vaccine than after other influenza vaccines. Pharmacovigilance data collected by the company show no unexpected adverse events. (6) In practice, there is no reason to prefer the squalene adjuvant vaccine to existing vaccines for elderly people, whether or not they have underlying chronic conditions.