Progress in medical science, better diet and improved hygiene have made the world a healthier place for many.
How long people are likely to live is called life expectancy. In 1950, the world average was just 40 years. Now it is over 63 years.
Life expectancy is usually high in richer countries. The Andorrans live on average for 83.5 years; the Japanese live for 80.8 years.
Life expectancy is much lower in poor countries. People in Zambia live just 37.3 years; people in Mozambique live 36.45 years.
Vaccination programs have reduced the effects of some major diseases. The terrible disease smallpox was thought to be wiped out in 1977.
Some diseases are on the increase in poorer parts of the world. AIDS (Acquired Immune Deficiency Syndrome) is now killing huge numbers of Africans.
In some parts of the world, disease, lack of food and water and poor healthcare mean that one child in every four dies before reaching the age of five in poor countries like Afghanistan and Sierra Leone. World geography
In the USA and Europe less than one child in a hundred dies before the age of five.
In wealthier countries such as Italy and Switzerland, there is on average one doctor for every 350 people.
In most poor African countries, there is just one doctor for every 50,000 people.
The first vaccination ever was given in 1796 by Edward Jenner. He used cowpox matter to vaccinate against smallpox.