Scientists at UC Riverside have demonstrated a new, RNA-based vaccine strategy that is effective against any strain of a virus and can be used safely even by babies or the immunocompromised.
If you want to search for it yourself it's "Live-attenuated virus vaccine defective in RNAi suppression induces rapid protection in neonatal and adult mice lacking mature B and T cells" by Gang Chen, Qingxia Han, Wan-Xiang Li, and Shou-Wei Ding