Microencapsulation of Vaccine Antigens

Despite obvious successes in controlling most serious childhood infections, there is a need to develop cheaper and more effective programs in infant vaccination. However, with the knowledge that adults are susceptible to diseases once believed to be only relevant to children, these criteria are equally applicable to adult vaccination programs. Furthermore, with the emphasis on safety, the vaccine industry is slowly replacing existing vaccines with recombinant alternatives that are safer and less reactogenic than their nonrecombinant counterparts, yet also less immunogenic. Thus, any improvements to vaccines in the foreseeable future are likely to arise through the introduction of better adjuvants and delivery systems. For example, a single injection comprising primary and booster doses of vaccine would improve compliance in a cost-effective manner by reducing the number of visits to clinics or medical centers. Equally, administering existing vaccines orally would remove the trauma of injection and the reliance on medical staff to perform the injections. Many vaccines are dependent on a cold chain; improving the stability of vaccines would thus help to reduce the cost of vaccination. To tackle such issues, researchers have borrowed ideas from other areas of the pharmaceutical industry in an attempt to improve the performance of vaccines and reduce the cost of these important health-care interventions.