Is my sore throat from COVID-19 or from strep throat? What’s the difference? For starters, COVID-19 is a viral infection and like the flu, colds or other viral infections, these often are accompanied by respiratory symptoms. Strep throat is an infection in the throat and tonsils caused by bacteria called group A Streptococcus (group A strep). Group A strep bacteria are very contagious. Generally, people spread the bacteria to others through respiratory droplets or ...