Pea-Sized Gel Implant Could Eliminate Vaccine Booster Shots

Anyone who has prepared for international travel, or reared a baby, knows the hassle of staying on schedule through multiple courses of vaccinations. It'd be way easier if those required boosters came in pill form, but that's just not how vaccines work. Or it wasn't, until researchers came up with a tiny implant that stores a vaccine dose released when you take a pill.

The "remote-controlled drug depot" devised by German researchers is built around a highly flexible water-based hydrogel. The polymer can form a capsule that stays intact in the body until it's exposed to a substance that makes it release its contents. In this experiment, the trigger is fluorescein, a common compound used in medical imaging that's taken in pill form.

The new delivery system showed promising results in mice: a group of mice given hydrogel implants containing HPV vaccine, then later given the activating pill, showed the same immunity as mice who received the standard two injections. Mice given the hydrogel implant, but no activating pill, showed no immunity.

Naturally, the study has a long way to go before human tests can be attempted. But the idea of getting a full course of vaccinations in one doctor's visit, then activating booster doses by simply swallowing a pill, is more than just a convenience: it could be a huge benefit in the developing world, where tragically limited resources and the distance between patients and clinics conspire against the "come back in a few weeks for a booster" vaccine schedule. And around here, it could be a blessing for anyone who's routinely had to reschedule a vaccination appointment. Or any parent of a fussy baby (or adolescent) who hates getting shots. [Advanced Functional Materials via Wired]

Image: Raphael Gubeli/Gubeli et al., Advanced Functional Materials (2013)