Vasileva D, et al. - Researchers identified and analyzed human studies reporting measurements of C-reactive protein (CRP) levels in patients infected with H1N1 influenza at various levels of disease severity to test its utility as a biomarker in predicting infection severity. Ten studies were eligible for inclusion. Findings revealed a consistent association between significantly higher CRP levels in H1N1 influenza patients and development of a severe disease outcome. Compared with those with no severe disease outcome, 1.4- and 2.5-fold significantly higher CRP levels were found among subjects with H1N1-related pneumonia and patients who were hospitalized or died of the disease complications, respectively.