Since the beginning of human history, we have been at war with an invisible enemy. Microbes. These tiny organisms can spread terrible diseases. Ramses V, Pharaoh of Egypt may have died of smallpox; in 1918 a new illness called the Spanish Flu killed 50 million people in 18 months; and in the fourteenth century the black death killed more than a quarter of the population. In more recent times Covid 19 has changed the way we live. But there's good news too! Human scientists have learned to fight back. In the 18th century edward Jenner developed the first vaccine, and since the 1930s...