 This is a randomized, placebocontrolled, multicenter, partially blinded i.e., 100 mcg and 200 mcg IC43 with AlOH3,, respectively and placebo, but unblinded for nonadjuvanted IC43 i.e., 100 mcg wo AlOH3 phase 2 pilot study. The study population consists of male or female ICU patients with a need for mechanical ventilation for more than 48 hours, aged between 18 and 80 years. 