Sore throat, fever and formation of grey or white patch in the pharynx are the symptoms of:
Diphtheria
Diphtheria is an infectious disease caused by the bacterium Corynebacterium diphtheria, which primarily infects the throat and upper airways, and produces a toxin affecting other organs. It is spread (transmitted) from person to person, usually through respiratory droplets, like from coughing or sneezing.