Are Christians and Jews Kuffar?

Muslims are quite happy to call Christians and Jews 'kafir' but what does the verse below say?

S 5:57  Those who have believed, do not take those who have taken your religion as a quip and a game from those who were given the Book before you and the kuffar as protectors. And fear Allah if you are believers.

'Those who were given the Book AND the kuffar'. How, going by this verse, might the former be the latter? Notice that the 'clear and detailed' quran doesn't say: 'the other kuffar'.