IL6 and COVID-19: However, IL-6 appeared to be further elevated at 18 months versus 3 months after acute COVID-19, 4.0 ± 4.6 pg/mL vs. 2.5 ± 2.6 pg/mL (p = 0.006), with 19.4% of participants having IL-6 levels above the normal range at 18 months after COVID-19.