Both news articles I read about publication of this study in Science stated that this study indicated that boosters are not needed now.
So I read the actual article in Science. Can't say that I read it carefully because so much of it was clinical gobbledygook to me. However, I was looking for "booster" and the authors' opinion thereon.
I did not find the word booster or third shot or anything resembling what a layperson would consider a booster. I did not find anything in the article itself or the footnotes thereto which could be construed as the authors opining that this study indicates boosters are not now needed. IMO, that came from the authors of the news articles, not from the paper itself.
Besides, the article said it was not comparing durability of the 25 mcg dose with the 100 mcg dose as that comparison would require a clinical trial. By extension, it also does not speak to a 50 mcg booster which Moderna has proposed on top of two, 100 mcg doses.
A nice study from an academic standpoint, but to me, it has no relevance to the booster issue now in front of the FDA. Shame on the editorialization in the news article.