Does the Extra return next school year to class 3?

Question

After the anime stopped

Reiko (the Extra) was killed

that school year in 1998, right? Does that mean that the Calamity has stopped, or will it happen again next year?

Answer 1

Yes, it can happen again as the Extra being killed has happened before.

Earlier in the series, a former class 3 student Matsunaga was questioned about what happened to his class during a field trip. During this, it was revealed that Matsunaga had accidentally killed the Extra and for a short while, he remembered this, and he made a recording about it.

At the end, Teshigawara and Mochizuki are shown to be re-recording Matsunaga's message but differently. Since killing the Extra prematurely stops the Calamity for that year, they gave caution about the actions to take against the Extra since it was learning how to stop the Calamity and the fear of losing Izumi Akazawa that made Takako Sugiura insane and rally the students to try and kill Mei.

As such, if killing the Extra was enough to permanently stop the Calamity, then the events of Another wouldn't have happened. However, since this has been the second time that the Extra has died, then we can assume that the Calamity can and will happen again considering that Another 2 was announced back in 2012.