葡萄牙科学家说，他们研发出一种实验性疫苗能防止蛀牙，而它已在实验室的老鼠身上证实有效，这将有助开发防止人类龋齿的疫苗。

• Portuguese scientists said they had developed an experimental vaccine against tooth decay which was successful in laboratory tests on rats and could pave the way for a version that works for humans.