Catalysis of the transfer of a solute or solutes from one side of a membrane to the other according to the reaction: iodide(out) + Na+(out) = iodide(in) + Na+(in).
Catalysis of the transfer of a solute or solutes from one side of a membrane to the other according to the reaction: iodide(out) + Na+(out) = iodide(in) + Na+(in).