Single-Dose Vaccine and Booster

Vaccines are no fun—particularly for small children—and the ability to deliver multiple doses in a single shot would save a lot of tears and anxiety. The problem is that vaccines are unstable and break down easily at body temperatures, so multiple shots are needed to provide optimum protection. But now a microscopic container has been developed that could allow secondary and even tertiary doses to be released over time. By altering the thickness of the polymer walls, the time to degrade and release their contents can be varied to stagger the doses by weeks or even months.

The time-release microparticles were tested on mice. A single injection containing a mix of vaccines was administered. The individual polymer cubes were filled with different proteins that were designed to trigger a unique immune response. As planned, the proteins were released at nine, 20 and 41 days.

The team has plans to develop particles that can last up to 200 days in the body before releasing their contents. The technique may also someday be applied to deliver multiple vaccines to protect against a broad range of diseases in a single shot.