So almost 40% of humanity does not have HSV-1.

Astronaut selection is already severe. You don't get selected if you have tuberculosis, diabetes, amputations, or deafness. Once selected, you won't go on the launch if you are sick with the flu.

It doesn't seem like HSV-1 needs to be a problem in space. Simply add that to the gigantic list of conditions that prevent space travel.

I highly doubt that HSV-1 is anywhere near 60% in the pool of astronaut candidates. Disease presence is correlated: if you have one, you probably have another. Since lots of other diseases would already be disqualifying, adding HSV-1 to the checklist won't strike off very many potential astronauts.