[etiam]

The premise here seems wrong. SARS-2 vaccine development rides on the development of SARS vaccines. That's already almost two decades. Probably boosted halfway by research to manage the even more concerning MERS.

And that's not even the start of it. Those R&D efforts ride on about a century of basically successful vaccination against viral diseases. Sure, there are plenty of species that are too slippery for now, and coronaviruses do their due diligence in attempts to escape the immune system, but to my understanding it's not a comparison on the same scale to ask for overcoming the immune evasion arsenal of a eucaryotic parasite with a complex multistage lifecycle, and Plasmodium is arguably in the big league within that category.