Vaccinology: past achievements, present roadblocks and future promises.

Of all the branches of modern medicine, vaccinology can claim to be the one that has contributed most to the relief of human misery and the spectacular increase in life expectancy in the last two centuries. It is the only science that has eradicated an infectious disease-smallpox-responsible for 8-20% of all deaths in several European countries in the 18th century. Other disabling and lethal diseases, like poliomyelitis and measles, are targeted for eradication. Currently, it is estimated that immunization saves the lives of 3 million children a year but 2 million more lives could be saved by existing vaccines. The success of vaccines in controlling and eliminating diseases has, paradoxically, been the cause of a revival of the anti-vaccination movement which in the absence, in developed countries, of many erstwhile common infectious diseases such as diphtheria, tetanus, polio, pertussis, measles, rubella and mumps has come to believe that vaccination is not only no longer necessary but is even dangerous. This is because it accepts, as "reactions", any untoward health event that occurs after administration of a vaccine. Most vaccine "reactions", therefore, appear to be more frequent than vaccine-preventable diseases. Public Health Authorities, aware of the great value of vaccines to society, are facing an uphill battle to get them accepted by a growing proportion of so-called educated minorities, thus endangering disease elimination. Other developments, in the last two decades, that have hampered vaccine usage have been the exploding costs of research, development and manufacture of new vaccines and the emphasis still placed on therapy in preference to prevention in medicine. This has led to the erroneous perception that vaccines are expensive although they are, in most cases, more cost-effective than the popular wait-see-treat approach. A favorable trend for vaccinology has been fueled by recent major breakthroughs in the sciences of immunology, molecular biology, genomics, proteomics, physico-chemistry and computers that promise a bright future for prevention, not only of acute infectious diseases, but also treatment of conditions like chronic infections, allergy, auto-immune diseases and cancer where some malfunctioning of the immune system is thought to play a part. Vaccines are being made more user-friendly by the development of combined vaccines and less painful and invasive inoculation techniques than the traditional syringe and needle. Recent new initiatives, like the Global Alliance on Vaccines and Immunization (GAVI),which are gathering new sources of funding for vaccination, should be beneficial for vaccinology.