Inside a vaccine clinic in Sierra Leone
10 June 2011 Last updated at 13:39 BST
The BBC's medical correspondent, Fergus Walsh, has been to Sierra Leone to see what progress is being made in improving child health. It has one of the highest rates of child mortality, but there are signs of improvement.
Free healthcare was introduced last year for pregnant and breast-feeding women and children under five. Immunisation is another key tool in preventing deaths in childhood.
40% of child deaths a year are caused from pneumonia and severe diarrhoea - both are preventable through vaccination.
Fergus Walsh went to a vaccination clinic, 170 miles from the capital Freetown, where they are giving the jab against pneumonia.
A vaccine against the most common cause of diarrhoea, the rotavirus, also exists - but is not available in poorer countries.
A summit is being held in London on Monday 13 June, asking world leaders to pledge more money to enable these two vaccines to be rolled out across the world.