In 1988, polio paralysed some 350,000 children a year in more than 125 countries. Thanks to mass vaccination, wild poliovirus now circulates endemically in only two countries, Afghanistan and Pakistan, with tens of cases to around a hundred a year. According to the Global Polio Eradication Initiative, over 20 million people are walking today who would otherwise have been paralysed.
That's the estimate from a WHO-led study published in The Lancet in 2024, covering the half-century since the Expanded Programme on Immunization was launched in 1974. It works out to about six lives saved every minute, mostly infants. The measles vaccine alone accounts for around 60% of those lives.
According to the World Gold Council, about 216,000 tonnes of gold have been mined in all of human history. Because gold is so dense (19.3 tonnes per cubic metre), it would fit in a cube about 22 metres on each side, roughly the height of a seven-storey building. Strikingly, about two-thirds of it has been mined since 1950.