Although development of a jab for the H5N1 strain of avian flu is well under way, other strains are receiving less attention — and political obstacles to research could hamper progress. During the summer of 2023, fur farms in Finland that raise mink, foxes and raccoon dogs were hit by an outbreak of H5N1 avian influenza. Nearly half a million animals were culled during the outbreak, and Finnish health officials were on high alert. “We worried that under circumstances where many animals are confined in small places, the pathogen might rearrange genetically into a new pandemic virus,” says Hanna Nohynek, a vaccinologist and chief physician at the Finnish Institute for Health and Welfare in Helsinki.
Finnish authorities responded by offering to vaccinate groups at high risk of H5N1 exposure, including fur-farm workers, laboratory technicians and veterinarians — the first and only country to do so. This was a precautionary measure: although H5N1 is spreading among birds and other animals all over the world, human cases are still rare. But this state of affairs could change. An H5N1 pandemic “might be the big one that many of us have worried about”, says Ashish Jha, a physician and dean of public health at Brown University in Providence, Rhode Island.