Hello and welcome to more or less on the BBC World Service. I'm Lizzie McNeil.

The World Health Organization has reported that so far this year, over 47,000 adults and

children in the European area have been infected with measles. The number for the whole

of last year was almost 24,000 and in 2016 it was a little over 5,000. So, why are the numbers

growing? Well, it's all to do with how contagious measles is and the number of people who have

vaccinated against it. The invention of vaccinations has helped contain many of the more contagious

diseases and it all began with a disease you may have read about but never encountered.

Smallpox affected people before records began, as trade routes developed and empires expanded

the virus spread. By the 18th century an estimated 400,000 people in Europe died every year from

smallpox. By the late 19th century, fatality rates and infants from smallpox reached 98% in

Berlin and 80% in London. People have been trying to fight the disease for centuries and there's

a lot of evidence to suggest that civilizations in Egypt and the Middle East had discovered the

process known as verilization. By taking a piece from a lesion on an infected person and

transferring that matter into a cut on a non-infected person, that non-infected person would be

protected from the disease. In 1721 we got the first statistical evidence for how successful

verilization was during an outbreak of smallpox in Boston, Massachusetts. The Reverend Cotton

Mather persuaded Dr. Zabdiel Boylston to inoculate volunteers. During the epidemic roughly half of

Boston's population contracted the disease. The fatality rate was 14%, but the rate for those

who were virulated was 2%. It wasn't until 1796 that a major breakthrough occurred. Edward Jenner,

an English physician, noticed that people who'd had a disease called cowpox did not get smallpox.

So Jenner inoculated a child with cowpox. Initially the child developed a mild fever and lost

appetite, but after nine days had fully recovered. Jenner then inoculated the boy with smallpox.

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