Merck does not completely understand the mechanism of action of aluminum adjuvants.
From Merck patent WO2008112125A1
Merck has filed a patent application WO2008112125A1 for an invention that adds an ISCOM-type adjuvant to the HPV vaccine Gardasil, which contains aluminum adjuvant AAHS. In this patent application, Merck states the following:
While the mechanism of action of aluminum adjuvants is not completely understood, it is generally thought that for optimal immunostimulating effect, the targeted antigen should be adsorbed onto the aluminum in a vaccine preparation (see Lindblad, supra).
In other words, they are using an aluminum adjuvant because it stimulates the immune response, although they don’t fully understand it.
There is no way to deny the harm of aluminum adjuvants while their mechanism of action remains unclear. If someone ignores this fact and still claims that aluminum adjuvants are "safe," then they are undoubtedly a fraud.
Medical professionals with conflicts of interest may say, "We are continuously collecting data and conducting more detailed evaluations," but from the perspective of ordinary people, it can only be described as "assessing harm through empirical observations in human experiments."
AAHS is a complex of aluminum hydroxide (Al(OH)₃) and phosphate (PO₄³⁻), and its surface charge varies depending on pH and environmental conditions. However, Al(OH)₃ has a positive charge and may interact electrostatically with, and adsorb, DNA, which is inherently negatively charged.
Merck patent WO1998035562A1 discloses a method to address the problem of plasmid DNA adsorption by aluminum adjuvants by adjusting the surface charge of the adjuvant to be negative. This adjustment is likely intended to inhibit the plasmid DNA adsorption to the adjuvant through electrostatic repulsion, as the plasmid DNA is negatively charged.
Considering the disclosures in this patent, it can be inferred that Merck had a thorough understanding that controlling the surface charge of aluminum adjuvants could regulate their interactions with plasmid DNA.
Given the example of Gardasil, where AAHS adsorbed DNA, it can be inferred that there was little to no DNA adsorption inhibition effect in Gardasil. For instance, if the surface charge of AAHS is neutral or positive, DNA is likely to bind more readily to AAHS.
While it is certainly plausible that Al(OH)₃ adsorbed DNA regardless of the surface condition of AAHS, I believe that by understanding the surface characteristics of AAHS, we can better grasp the core of this issue. Based on the patent disclosures, I do not believe Merck lacked an understanding of the interaction between AAHS and DNA.
Please also refer to my previous posts.
