UK Raises H5N1 Bird Flu Risk to Level 4 Amid U.S. Debate on Cow Vaccines

Jul 29, 2024, 12:21 PM

The UK has increased its risk assessment for the H5N1 bird flu from Level 3 to Level 4, indicating sustained and/or multispecies mammalian outbreaks, increasing human zoonotic cases, or limited person-to-person spread linked to zoonotic exposures. This comes amid a debate in the U.S. about the potential use of cow vaccines to control the spread of bird flu in herds. Experts are divided on the efficacy of such vaccines, with some arguing that vaccination efforts could backfire and cause harm. There are currently no reports of flock viral deaths or serious human cases from the current bird flu strain, which is described as very mild. Continual reinfection by migratory water fowl has been noted. Some scientists believe that resorting to vaccines may be an admission that containment efforts have failed, and advocate for natural immunity to settle in.