Epidemics, the rapid spread of infectious diseases to a large number of people within a short period of time and over large regions (pandemics), are major threats for humanity. The Spanish flu, for example, claimed about 50 million lives 100 years ago. Although the more recent influenza pandemics of 1957, 1968, 1977 and 2009 were milder, they nevertheless show the great pandemic potential of viruses. The seasonal flu alone leads to 290,000 to 650,000 deaths worldwide – every year. Other viruses, like the Ebola or the Zika virus, hold the potential to cause devastating pandemics around the world.
Vaccinations are the best prevention against epidemics and pandemics. However, current influenza vaccines are comparatively ineffective: the virus changes its surface frequently and so quickly that current vaccine development methods are simply too slow. By the time the vaccines are ready for distribution – about 6 months after strain identification – the viruses may already have changed significantly.
Source: Bill & Melinda Gates Foundation