WZH±coupling in SU(2)×U(1) gauge models

In the framework of SU(2)×U(1) electroweak gauge models with standard fermion assignments we derive the most general expression for the $\mathrm{WZH}$ vertex which is the most relevant for the production of charged Higgs particles. We show that the vertex only exists with an appreciable strength in models with a rather complicated Higgs sector. Experimental detection of charged Higgs particles seems therefore very difficult.