Climbing rose no new growth yet

Morning all ,I'm getting slightly concerned about two climbing roses I have . They started to produce new growth mid march ish  ( small buds ) but we had some frost which killed the new growth , since then they have been dormant and no new regrowth has appeared . They are 6/7 years old and obviously well established and always been healthy , should I assume they are dead or should I leave them a bit yet to see if any new shoots appear from them , thanks in advance .