MF59 is a proprietary adjuvant (we’ll get to this later) that is used to increase the efficacy of vaccinations by further stimulating the body’s immune response. Is it the harbinger of “pharmageddon” as the antivaccination crowd would like you to believe? Probably not.
But first lets go back to what is an adjuvant and why are they in our vaccinations to begin with. Adjuvants are agents that modify effects of other agents, you know, like drugs or vaccinations. The use of purified vaccine antigens have created vaccines that are better “characterized” but the tradeoff is that these vaccines are not an immunogenic as their more crude redneck vaccine cousins*. One thought is that the crude vaccine kinfolk also had some immunostimulatory components in the rough formula like ligands for Toll-like and other immune receptors. Studies of adjuvants are starting to build a role at the molecular level for activating specific aspects of our innate immune system.
Also adjuvants are important for certain populations who would otherwise not develop the proper immune response to vaccination like a young adult receiving the vaccine. So if it’s so good why is everyone hating on MF59?
A previous study demonstrated that in non-autoimmune mice that were injected with squalene (a component of MF59) were associated with elevated rates of lupus autoantibodies. This is possibly alarming but mice are mice and humans are humans and the fact that these BALB/c mice are inbred doesn’t necessarily mean MF59 is causing lupus in humans. A more recent study looking at MF59 in flu vaccines in humans suggest that it has a good safety outcome profile when compared to that of influenza vaccines lacking MF59.
MF59 has been claimed to be responsible for Gulf War Syndrome and anthrax vaccination sickness but there is no way that its possible. MF59 wasn’t the adjuvant used in the anthrax vaccination, it was aluminum hydroxide, another classically used adjuvant.
So when flu season rolls around again, I’m rolling up my sleeve for my yearly influenza vaccination and a little bit of MF59 for good measure.
*Early DPT vaccines used whole-cell agents rather than recombinant antigens.