Most vaccines consist of an inactivated virus to train the immune system to attack an invader. But such a system poses risks patients, especially when it comes to HIV. Like many vaccine researchers, those at the Massachusetts Institute of Technology are exploring alternative DNA vaccines.
Part of the difficulty with DNA vaccines is finding a way to deliver them to patients safely and with little pain. MIT researchers created a patch made of many layers of polymers embedded with the DNA vaccine to deliver it to the skin, Manufacturing Chemist reports. Microneedles penetrate about half a millimeter into the skin, implanting the polymer films. The films degrade when they come in contact with water and release vaccine over several days or weeks, depending on the number of polymer layers.
Delivering DNA vaccines has been tricky for researchers. One method involves injecting DNA under the skin and then using electrodes to create an electric field to open small pores in the skin to make room for the DNA to enter. The process is often painful and not always reliable.
"It's showing some promise but it's certainly not ideal and it's not something you could imagine in a global prophylactic vaccine setting, especially in resource-poor countries," Darrell Irvine, an MIT professor of biological engineering and materials science and engineering, told Manufacturing Chemist.
So far, no company has successfully developed a DNA vaccine. Merck ($MRK) tried a DNA-based flu vaccine, and others have attempted to use DNA to protect against HIV. An advantage to a DNA vaccine is time saved. Many manufacturers use viruses grown in chicken eggs, a costly and time-consuming process. DNA vaccines would also be more stable to ship and possibly store at room temperature.
And when a DNA vaccine is successfully executed, manufacturers will need an effective, low-cost and, hopefully, pain-free way to delivery it.