Smell of vomit

[Tyrionsbitch]

My little girl was sick in the night last night and, despite a protective mattress cover and a waterproof sheet, her mattress now smells of vomit. There is no stain and the mattress is dry, it just smells. What is the best/quickest way to get rid of the smell?

Bicarbonate of soda!!
I chucked a whole pack over the back of my car when my daughter was sick in there Christmas eve. Despite lots of cleaning the smell had lingered. One pack of this left for a few hours and then hovered up and there is no smell whatsoever anymore.

Fab, do I need to wet it first or does it work when dry?

I use dettol anti bac air freshener spray for this, my daughter gets travel sick so I keep a can in the car as the smell seems to linger long after a thorough cleaning

Yep! Bicarbonate of soda is the bomb! Sprinkle it on dry and leave it to sit for about 24 hours. If you can put it outside today during the day as well, do this with the bicarbonate of soda sprinkled ALL over it. It really is the only thing that works.
Also, buy a product called Sterizar. It's the one spray that will kill norovirus. Nothing else does other than hot water and bleach (definitely get the hot water and bleach going in that room so that you kill the germs- they can stay for up to two weeks and come back to bit your DD again). Sterizar has no odor and doesn't smell all 'chemically'. I also get the wipes.

Thanks for the tips, I poured a whole tub of bicarb on, left it for a few hours and it seems to have done the trick! I might invest in some of that sterizar too as it sounds good.