Magicalo Magical

After a virus turned many humans and other living things into monsters, many people died or moved out of major cities. At first, all people could do was to run away from the monsters. Soon, though, another virus allowed some people, magic users, to defend others from the monsters.

Koizumi Shizuku was inspired to protect others after she was rescued from a monster. However, she only has a small healing talent and she's had trouble getting her super-power team hired. She doesn't let this stop her, though, and soon discovers a great power within herself-- she can heal people who have already been turned into monsters! Now Shizuku does her best to protect and heal people alongside her team, while also working part-time at the store of a man she was able to heal.

(Source: MangaHelpers)