Highschool of the Dead volume 8 will be released this Spring, after a 2 year hiatus during which the author focused on his other manga, Triage X. The announcement was revealed in the 5th and 6th color volumes of HOTD. The anime, which has also been on hiatus, covered the first 4 volumes so there should be enough material for another season now.
For those who haven’t read the manga or need a refresher, the series follows a group of sexy high school students who work together to track down their sexy parents after a sexy zombie outbreak (noticing a theme?). Volume 7 ended with Rei Miyamoto reuniting with her mother. They attempt to head for an evacuation point but zombies block the way.