IgM V H amino-acid sequence of generated HBsAgspecific B cell clones. The germ-line sequence is given for each V H family, with indication of framework regions (FR) and complementary determining regions (CDR). Highlighted amino-acids correspond to N-additions (in the CDR3 region) and somatic hyper-mutation events, whether it results in a silent mutation (green) or not (red). Clones with identical BCR sequences are grouped together. Found at: doi:10.1371/journal.pone.0013137.s004 (0.02 MB PDF)  Reflections on Pandemic (H1N1) 2009 and the International Response Gabriel Leung and Angus Nicoll provide their reflections on the international response to the 2009 H1N1 influenza pandemic, including what went well and what changes need to be made in anticipation of future flu pandemics. There is general consensus that the only predictable characteristic of influenza viruses and pandemics is their unpredictability [1] . Given such uncertainty, reasonable application of the precautionary principle should prevail in the responses. Indeed many of the initial responses to the 2009 pandemic went well. Once isolated, the pandemic virus strain was shared immediately, specific diagnostic assays were produced and distributed worldwide, antivirals were available in many countries, vaccine development started promptly, and clinical trials demonstrating vaccine safety and immunogenicity were conducted rapidly.