Study finds long COVID symptoms lasted an average of 15 months Ryan Voyles 3 years ago Most COVID-19 long-haulers continue to experience symptoms nearly 15 months after contracting the virus, according to a study published this week from Northwestern Medicine.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.