I afraid that it is. If you put your hands in it a lot you can spread it to your other eye. And yes other people who are around a person with one may not even know it and touch something that person had touched after they have had there hands in their eyes and get one. Best thing to do is to keep your hands out of your eye and wash them with soap and water if you have to put them in your eyes. This will help cut down the spread of the stye.