It may depend if you live in Britain or in North America. In my research of "in this vein" I didn't find reference to other English-speaking lands.
From UsingEnglish.com, which seems to be a British site:
If you do something in that (or this) vein, you do it in the same
distinctive manner or style.
From Urban Dictionary
Talking/Thinking along the lines. Talking/Thinking about the same or
In that vein, what do you think about the health reform?
The prime minister was talking about the austerity measures in the
recession times. The opposition party also went on in that vein.
From Washington State University:
The expressions “in the same vein” and “along the same line” mean the
same thing (“on the same subject”)
If you are in the United States, it should therefore be fine to say it the way you are saying it. One could easily substitute "In this vein" with "On the same subject." However, in your sentence it would not seem right to me to say "along the same line" because wearing masks and being in class is not "along the same line." However, both regard the subject of the fall semester. That is how I analyze it. Others may have other opinions. I offer several definitions so you can choose the one that seems most appropriate for your personal situation.