Just checked it. It does not say, the results will be released in April, it says testing or the end of the project is April 30, 2024.
You will find that and details about it in the 10-Q from 11/20/2023 at the heading "NIH", e.g. "The Project with ULL under the NIH grant for our HIV vaccine is in its final year that will end on April 30, 2024. Mymetics has provided its commitments to this project by delivering the vaccines, which are tested in non-human primates."
I think, release could be before that date, after or even never, if Mymetics just sells that all.
By the way: Still some people seem to believe that Mymetics is not yet done completely. I always see bids for almost buying all outstanding shares (for nearly nothing).