(2) Hepatic disease Chronic hepatic disease is a risk factor for severe 2009 H1N1 disease [3] . The development of hepatocellular carcinoma occurs at a 2:1 to 4:1 ratio for males to females [67] . The prevalence of serum hepatitis B virus (HBV) is consistently higher in men than women [68] . Males are more than twice as likely to die from liver cancer, which suggests that men may be more sensitive to the effect of HBV infection on the development of liver cancer [69] . Men also are twice as likely to develop cirrhosis [70] .