So the way I read this statement, they explicitly say state "Pfizer has not conducted gain of function."<p>Then they later admit, " In a limited number of cases when a full virus does not contain any known gain of function mutations, such virus may be engineered to enable the assessment of antiviral activity in cells." (I'm not exactly clear what that means, but it reads like they do gain-of-function to me. I've learned that when people are usually unclear on very important statements it's often the worse interpretation that's true, otherwise they'd have a reason to be clear).<p>Then they quickly defend "It is important to note that these studies are required by U.S. and global regulators for all antiviral products and are carried out by many companies and academic institutions in the U.S. and around the world."<p>So I'd take this to mean one of two things:<p>1) Gain of function research is required & happening everywhere and they just stopped telling everyone because it's so political so we now weasel-word around it; if you were technical you'd understand<p>or<p>2) They are twisting words very hard in this press statement about what is "required"