CDC: Proportion of COVID-19 cases that are BA.5 continues to drop Ryan Voyles 2 years ago The COVID-19 landscape continues to diversify, with little more than half of all cases in the six-state region that includes Illinois now the BA.5 strain.To access this content, you must purchase 1 Year Health News Illinois Subscription or 1 Year Group Subscription - Up to 5 Users, or log in if you are a member.