Only My Vaccine Can Save the World From Zombie Apocalypse

Oikawa Yuu, who has been isolated in his home, believes he will die a virgin at the age of 21. This is due to the fact that the entire world has turned into a zombie-infested place... One day, a survivor arrives at Yuu's residence. The woman, who identifies herself as Sunny, administers a vaccine to Yuu that could potentially save the world from the zombies... however, as a consequence, Yuu acquires the power to revert zombies back into humans through sexual intercourse...?