I imagine it’s from past information that had been communicated on this topic (as the original poster alluded to), it very much was the general understanding that it is important to take the full course for the reasons mentioned, however I am not too surprised that it appears that is not the case, logically the initial claim didn’t make sense, but I figured that was because I’m not into biology much. Interesting to see the counter argument which makes much more logical sense to me.