When one twin gets sick, it's usually inevitable that the other will fall to whatever germ is in the house. I've given up trying to keep one from transmitting whatever it is to the other, for the most part.
My twins share everything: a room, sippy cups, toys, utensils, food. No matter how hard I try, it's impossible to keep them from sharing unless they are strapped down for hours which is just not possible.
Last week, Bunny Twin had a cold with a runny nose and sneezing. Buddy Twin had a milder version, but now he has an intestinal thing. I'm just waiting for the intestinal ax to fall on Bunny.
So how do you handle sick twins? Prepare for both to be sick. Keep medicines and supplies on hand because its even harder to drag two tots to the store. When you have coupons at the beginning of "sick season" -- which is right now! -- stock your medicine cabinet with pain reliever, Benadryl, saline nasal spray, etc. I actually used a Pediatelyte coupon earlier this year to buy powdered Pedialyte -- little packets that you mix with water. It was a very thoughtful choice as I had tried to keep Pedialyte on hand but it always expired before I could use it! The powdered stuff lasts longer, takes up less space, and today, I was very glad to have that on hand!
It's also good to try and have bland crackers like Saltines, as well as applesauce, jello and rice on hand. If you have a little one who needs nourishment but is having stomach issues, these are good things to feed them. (Or you, for that matter, if you come down with it too!) Stock up when there are coupons and sales.
Also, be sure to stock up on disenfectant. Keep the house cleaner than normal to try and keep the illness at bay, particularly for yourself! Don't forget little spots like lightswitches, doorknobs, cabinet handles, etc. Wash bedding, blankets, comfort toys, throw blankets, etc. often to keep them clean and germ free. And wash your own hands often.
Here's a decent article on when twins are sick.
And now, I'm off to bed! I need to take care of me, too!