By Michelle Strikowsky August 10

A new study by the Centers for Disease Control and Prevention concluded that a global flu pandemic would not result from simple genetic mutations to the A(H5N1) subtype of the avian influenza virus. Despite this finding, researchers warned the virus could still convert into a strain transmissible from person to person.

Currently, avian flu has only sporadically resulted in bird-to-human transmission, although there is some evidence that the H5N1 viruses are becoming more capable of causing disease in several species of mammals. The concern that the H5N1 "bird flu" virus could blend with a human flu strain and mutate into a virulent version capable of sparking a pandemic prompted the CDC researchers to study the effects of such a hybrid strain. They exchanged some of the genes from A(H5N1) with a highly contagious strain of human influenza and injected it into ferrets. The result was neither efficient transmission among the animals nor an illness as severe as the original bird flu strain. Despite these results, scientists warned that only a few hybrids were tested of the many that can potentially be created.

Several Institute of Medicine reports address the threat of pandemic influenza. Both Microbial Threats to Health: The Threat of Pandemic Influenza and The Threat of Pandemic Influenza: Are We Ready? Workshop Summary discuss ways the United States and the global community can be better prepared to anticipate and mitigate an influenza pandemic. In addition, the workshop report considers the steps that individuals and societies might need to take to optimally prepare for the next disease pandemic. The published proceedings from a symposium on pandemic influenza research outline gaps in research and priorities for advancing research on pandemic influenza.