Till the end of the 20th century, vaccines managed to deal with some of the worst evils of humankind: smallpox, measles, mumps, whooping cough, diphtheria or polio. There was a moment when the new intelligent drugs and high technologies almost turned vaccines into something obsolete.

But after the anthrax attacks in US following 9/11 event, the vaccine regained its importance. But it's not only about bioterrorism. Spectacular advance in immunology, virology and genetics have given it a great boost.

And we must not forget that vaccines have failed against their most important challenge: HIV. In the 80s, researchers tried to apply the same method against HIV as they did with polio or smallpox: they turned on the virus to teach the immune system how to reject the real infection. But HIV appeared to be too sophisticated for this clumsy technology. It was hiding inside the cells of the immune system to avoid being detected and suffered from some extremely rapid mutations with which the body's defense could not keep the pace.

Only recently researchers have understood that vaccines do not confer direct immunity, but just speed up the reaction of the immune cells, helping them to keep the pace with pathogens. But this has failed with tuberculosis and malaria, too, not only with HIV. Researchers still have hopes that in about a decade, an anti-HIV vaccine will be made.

But the new vaccines could also stop heart diseases, many times caused by fatty deposits. The accumulation of cholesterol on the arterial walls could induce, as it seems, an inflammation caused by bacteria. The normal immune response disrupts them so that they are turned vulnerable to cholesterol action. A vaccine that could impede the emergence of this initial infection could avoid, in the opinion of the specialists, the chain of events that would cause a heart attack.

But the greatest challenge of the vaccines would be cancer. At first sight, cancer has nothing to do with an infection. Moreover, the cancer cells are not unknown, they do not come from outside. But researchers have shown that the immune system can be trained to look for tumors. Dendritic immune cells that signal infections to the immune cells have already been trained to detect a protein present in colon and lung tumors.

Perhaps the most imperative necessity for vaccines is determined by the failure of the antibiotics, the so-called antibiotic resistance. For example, if in a chicken farm an epidemics of respiratory infection breaks out, the veterinary will apply enrofloxacine to all birds. This antibiotic can kill the respiratory pathogen but does not kill the Campylobacter bacteria found in their guts. These germs do not harm the bird, but now they do have less competing bacteria and multiply, propagating their genes that helped them resist the antibiotic.

The bacteria can pass through veterinary control in slaughterhouses and can be found this way in the chicken wings, breast or thigh you eat. Campylobacter bacteria cause severe food intoxications in humans. Negligent washed hands or not properly cooked meat can cause you trouble for several days. This indiscriminate use of the antibiotics turns against us and only new intelligent vaccines will save the day.