Va. Code § 19.2-274
If at such hearing the judge determines that the witness is material and necessary, that it will not cause undue hardship to the witness to be compelled to attend and testify in the prosecution or grand jury investigation in the other state and that the laws of the state in which the prosecution is pending, or grand jury investigation has commenced or is about to commence (and of any other state through which the witness may be required to pass by ordinary course of travel) will give to him protection from arrest and the service of civil and criminal process, the judge shall issue a summons, with a copy of the certificate attached, directing the witness to attend and testify in the court where the prosecution is pending, or where a grand jury investigation has commenced or is about to commence at a time and place specified in the summons. In any such hearing the certificate shall be prima facie evidence of all the facts stated therein.
Va. Code § 19.2-274