CRP and susceptibility to pneumonia measurement: Whereas vaccine efficacy was not significant for CXR-confirmed pneumonia (9%; p = 0.38), vaccine efficacy was significant when measured against CXR-confirmed pneumonia in conjunction with a CRP level of 120 mg/l or more (35%; p = 0.03) or a procalcitonin level of 5 ng/ml or more (33%; p = 0.04).