Is someone who follows other religions considered a Kafir?

"Whoever follows a religion other than Islam is an infidel (kafir) and will abide eternally in Hellfire, as indicated by many verses from the Holy Quran, including His (Allah's) saying: 'Certainly, disbelievers are those who say, "Allah is the Messiah, son of Mary,"' and His saying: 'And whoever desires a religion other than Islam, it will never be accepted from him, and in the Hereafter, he will be among the losers.' Muslims have unanimously agreed on this ruling."