Mobile, active, always on the move – that’s people nowadays. Not only do they carry bags and rucksacks around with them, but also… … bacteria, viruses and pathogens. And they’ve done so for centuries: Siena, in the 14th century. 100,000 people live here. The cathedral is to be enlarged. Construction work has begun. Then, the plague strikes the city. It wipes out two thirds of the population… and brings the construction work to an abrupt end. For Rino Rappuoli, a native of Siena, this is more than just a ruin. Today, I consider it a monument to infectious diseases; because every day it reminds us of how a disease like the plague can destroy an economy and most of a city’s population –in such a short time. The biologist has dedicated his scientific life to the development of vaccines. He created them against such dangerous diseases as diphtheria, influenza and meningitis. And to do that, he developed entirely new methods! Back then, the plague still needed around three years to spread. Today, the speed has increased. Take bird flu, for instance – one day it’s in Hong Kong, a week later in America, Europe and the whole world. Diseases spread much faster today, they’re far more dangerous, and we must always be prepared. In developing countries, infectious diseases spread very rapidly when no vaccines are available. That’s why Rappuoli considers it crucial that children be vaccinated. In industrialized countries, over the past hundred years or so, vaccinations have contributed to a doubling of life expectancy. He wants this effect for developing countries as well. Vaccination is probably the medium of intervention that has had the greatest impact on humanity. With vaccines, life expectancy can be increased and the gap between rich and poor reduced. And to do that, the vaccine expert has also set up a non-profit institute in Siena that is working on vaccines for developing countries – to fight infectious diseases that only occur there. Our immune system has to be able to fight off dangerous pathogens. Vaccinations support this process by forming antibodies. The germs usually enter the bloodstream via droplets, through the nose and throat. If the immune system recognizes them as foreign bodies, it sends out the appropriate antibodies – which then attach themselves to the surfaces of the intruders and destroy them. But there are some pathogens that are resistant to this, such as Meningitis B. The disease starts relatively harmlessly, but Meningitis and blood poisoning can then lead on to amputations or death. In the early 1990s, when researchers began to decipher the human genome, Rappuoli sensed it might help him in his fight against Meningitis B. The problem: the immune system does not recognize meningococcal B bacteria as foreign bodies. The immune cells do not attack them, and the bacteria can proliferate unchecked. Rappuoli has the genetic information of the pathogen deciphered, and searches for starting-points in his fight against the disease. He finds them – and becomes the first researcher to “crack the code” of his biggest enemy. We suspected that we’d stumbled across a goldmine of new antigens and thought: maybe we can create a vaccine from them. The new method does not take breeding of the pathogens as its starting point, but the genetic blueprint. Rappuoli calls this “reverse vaccinology”. It turns out to be a revolution. For the first time, we’d designed a vaccine against Meningitis B – starting with information from the genome in the computer. From that information we created a vaccine, which then went into production. This serum only contains the precise components that are necessary for immunization. And there’s a further benefit too: Of course, the syringe still hurts a bit at the injection site on the arm or the leg. But there are no serious side effects any longer. Since 2013, Rappuoli’s vaccine against Meningitis B has been approved in 38 countries. Following preventive vaccination, no more serious cases have been registered there. Rappuoli’s method enables much faster reactions to epidemics, and better protection against diseases where traditional methods have failed so far. A great deal has already been achieved for vaccination protection in children. The focus is now moving to other targets: vaccines as medication against cancer, or against Alzheimer’s. He is working on these, too. I’m very proud, not of the invention itself, but rather its usefulness for the population – to know that people are no longer suffering and children no longer dying, thanks to the introduction of the vaccine. Rino Rappuoli’s life’s work has saved thousands of people from life-threatening diseases, and will continue to do so. So that something like this, which occurred over 600 years ago, will never happen again.