An outbreak of H5N1 bird flu among cattle in the United States—the first known time the virus has spread into these mammals as hosts—is raising questions about whether this highly pathogenic influenza virus could become a human epidemic threat. 

Four cases of H5N1 infection in people – all of them farm workers in close contact with cattle – have been confirmed, but there has been no known onward transmission to others.  However, the virus has adapted so there is more mammal-to-mammal transmission in multiple places in the world.  Global health security experts say the virus is not considered a current risk to the general population, but they caution that the H5N1 risk level is not static. It could change—up or down—as the virus mutates. 

“While there have been just a few confirmed cases in people, CEPI’s approach for the moment is one of calm urgency,” says Nicole Lurie, CEPI’s Executive Director for Preparedness and Response. “It’s much better to be ahead of the curve than behind it, so you have a greater chance of containing an outbreak. We think of preparation actions a bit like putting our shoes on in case we need to start running.” 

Since CEPI is a ‘no-regrets’ organisation that wants to act as swiftly as is warranted, it is now ‘preparing to respond’ to any change in the H5N1 threat level.  CEPI has pulled together a cross-departmental group of its experts–including epidemiologists, vaccine R&D specialists, regulatory, preclinical and clinical testing, and manufacturing experts–to monitor the outbreak and initiate pre-emptive steps that could put the world ahead of H5N1 if it were to pose a greater human threat.