The VBSCan COST funding allows to reimburse expenses to participants who are enrolled in institutes located in one of the COST Countries Participating the Action, that are the 24 ones listed here in the table "Participations":
http://www.cost.eu/COST_Actions/ca/CA16108?parties
Specific recommendations to be followed to claim for reimbursement can be found at this link.
The general COST rules about reimbursements can be found in the COST Vademecum, linked here.
In case you are coming from a British institute, please consider that because of the uncertainty connected to the Brexit procedure expenses might become not eligible for reimbursement, as detailed in this COST communication.