‘But if Voldemort used the Killing Curse,’ Harry started again, ‘and nobody died for me this time – how can I be alive?’ ‘I think you know,’ said Dumbledore. ‘Think back. Remember what he did, in his ignorance, in his greed and his cruelty.’ ... ‘He took my blood,’ said Harry. ‘Precisely!’ said Dumbledore. ‘He took your blood and rebuilt his living body with it! Your blood in his veins, Harry, Lily’s protection inside both of you! He tethered you to life while he lives!’ ‘I live ... while he lives? But I thought ... I thought it was the other way round! I thought we both had to die? Or is it the same thing?’
If it's so then can Voldemort not die because Harry's blood once flowed through Voldemort’s veins? Someone please clarify.