From h+ Magazine: "For now, the best way to supplement the body's own defenses is through vaccines, but vaccines are far from a panacea. Each vaccine must be prepared in advance, few vaccines provide full protection to everybody, and despite popular misconception, even fewer last a lifetime. For example, smallpox vaccinations were lifelong, but tetanus vaccines generally last 5-10 years. There is still no vaccine for HIV infection. And when it comes to bacteria like tuberculosis, current vaccines are almost entirely ineffective. What's more, the whole process is achingly indirect. Vaccines work by first stimulating B cells and T cells in order to induce production of antibodies. They don't directly produce the needed antibodies. Rather, they try (not always successfully) to get the body to generate its own antibodies. In turn, stimulation of T cells requires yet another set of cells - called dendritic cells - and the presence of a diverse set of molecules called the major histocompatibility complex, creating still further complexity in generating an immune response. Our best hope may be to cut out the middleman. Rather than merely hoping that the vaccine will indirectly lead to the antibody an individual needs, imagine if we could genetically engineer these antibodies and make them available as needed. Call it immunity-on-demand. At first blush, the idea might seem farfetched. But there's a good chance this system, or something like it, will actually be in place within decades."