UNICEF is the world's largest distributor of vaccines to the developing world, supplying vaccines for 36% of the world's children.
In emergencies such as conflict or a natural disaster, we deliver vaccination campaigns to help protect vulnerable children from preventable diseases when health services are down.
There's still a lot of work to be done, but today, 4 out of 5 children are being immunised – that's more than ever before. Find out more in this photo gallery, or visit our page on immunisation and vaccines.
This four year old lives in a remote area of Mongolia. She's just been immunised against measles and rubella by a team of vaccinators who travelled by car, hand-drawn ferry, reindeer and foot to reach the children in the area where her family, nomadic reindeer herders, currently live.
© UNICEF/NYHQ2012-1732/BRIAN SOKOL