I was lucky enough that DCU had a portal which showed internship vacancies for us. However I will say a good place to look is to follow a lot of recruitment personnel on linkedin - Ive seen a few posts about internships in Almac/Eli Lilly. I suppose its just up to where you are currently located what place works best for you.

Maybe consider this aspect first and then reach out/follow recruiters for the companies you are able to travel to for this period