Phylogenetic analysis revealed the central roles of two African countries in the evolution and worldwide spread of Zika virus.
Shen S, et al. Virol Sin. 2016.

"Zika seems to have possibly originated in or spread from Senegal"

Of course it does, the genome encodes for selenoenzymes, that's impossible if it doesn't come from an area with selenium and lots of it. Senegal, It has the second largest deposits in the world.

Now, here's the funny thing you'll notice. Zika in Senegal?

There ain't none to speak of. Why would an area that's the source of this pandemic not be bothered by it?

Easy, with enough selenium in the blood, the virus takes what (remember its genome encodes for selenocompounds, where's it get Se from? You!) it needs and you ave enough still for your body to still be able to make the chemicals the immune system needs to kill this virus (Glutathione peroxidase, "GPx3").

so people there are not bothered by it. If they leave though and have the virus and no longer eat a high selenium diet (which is automatic in Senegal) then the virus takes over. They Are only immune while they're there and anybody is.

Look what happened to this poor bastard:

Jan 28, 2016 - A biologist from Colorado State University, Brian Foy, was bitten by mosquitoes numerous times in Senegal and fell ill with Zika after returning ...

He left the area. If he stayed there he wouldn't even know he had it., You'll no doubt find numerous example of people who had been to senegal and who test seropositive for zika antigens but never got sick.

So, because Se is the key here there can be no vaccine, ever. There's no point in training the immune system to fight it ,it can't without Se. And if you have Se you don't need the immunization anyway.

Now, what you'll also find is a variant of the virus without the Selenoenzyme encoding, possible even in Asia. This is what happened with ebov, the virus originates in Asia and is nonlethal (Reston strain) but mutated in the Se rich soils of Africa, pickup a gene for a homologue of a human immune system gene that contains Se. The exact same thing happened with Keshen's disease too, Wikipedia has a good write up on this.

Point is two brazil nuts a day and Ziko isn't going to bother anybody and will just go away. It's a localized deficiency disease that only affects people in areas of low or no selenium.