The preliminary conclusion of the current study suggests that SFI might be beneficial to patients with HF. More rigorously designed trails with high methodological quality are necessary for further proof. Genome Stability of Pandemic Influenza A (H1N1) 2009 Based on Analysis of Hemagglutinin and Neuraminidase Genes Influenza A virus (H1N1), which arose in 2009, constituted the fourth pandemic after the cases of 1918, 1957, and 1968. This new variant was formed by a triple reassortment, with genomic segments from swine, avian, and human influenza origins. The objective of this study was to analyze sequences of hemagglutinin (n=2038) and neuraminidase (n=1273) genes, in order to assess the extent of diversity among circulating 2009-2010 strains, estimate if these genes evolved through positive, negative, or neutral selection models of evolution during the pandemic phase, and analyze the worldwide percentage of detection of important amino acid mutations that could enhance the viral performance, such as transmissibility or resistance to drugs. A continuous surveillance by public health authorities will be critical to monitor the appearance of new influenza variants, especially in animal reservoirs such as swine and birds, in order to prevent the potential animal-human transmission of viruses with pandemic potential. Influenza A viruses belong to the Orthomyxoviridae family, and have a genome composed of eight segments of single-stranded, negative-sense RNA. Their surfaces are composed by a lipid envelope, originated from the plasmatic membrane of infected epithelial cells, and two antigenic proteins: Hemagglutinin (HA) and Neuraminidase (NA); these two antigens exhibit higher variability compared with their remaining proteins [1] . Depending on the extent of variability of two surface proteins, until now are known 16 HA (H1-H16), and 9 NA genotypes (N1-N9), respectively, which can be combined in different combinations [1, 2] .