Vaccination for Disease Prevention and Control: the Necessity of Renewed Emphasis and New Approaches

Vaccination was discovered initially as an effective measure to prevent infectious diseases by Edward Jenner, Louis Pasteur and other pioneers several hundred years ago.[1] Since then, efforts to develop vaccines have been rather sporadic and limited, making prophylactic vaccination available only for a limited number of infectious diseases. Prophylactic vaccination has a proven record of success in childhood immunization programs worldwide, indicative of the feasibility and necessity of developing additional prophylactic vaccines. This is not just because of their unavailability for the majority of extent infectious diseases caused by known pathogenic species of viruses, bacteria, protists, fungi and helminthes, but also for the emergence of new pathogens that is estimated to occur at a rate of 3 per year.[2] Serious investment in vaccine development becomes all the more urgent considering the tenacity of infectious diseases in several ways. First, most of them are impossible to eradicate, since they are zoonotic diseases, which circulate often via vector transmission among domestic and wild animals.[3] Secondly, our reliance on treatment, e.g. chemotherapy over prevention for disease management has become increasingly untenable, resulting from the development of drug-resistance by the pathogens. Finally, lasting cure of infectious diseases has long been considered to require post-therapeutic development of effective immunity, since no drug used for chemotherapy is expected to reach all the intended targets, regardless of its dosages and frequencies of applications. A good example for this is perhaps the “Mississippi baby” who turned HIV-positive two year after what was thought to be the first case cured by anti-retroviral therapy when applied to the newborn.[4] Taken together, there is clearly a need of our renewed emphasis on immuno-prophylaxis of all diseases by vaccination.