Like bird flu rages among birds and dairy cattle across the United States, Georgia became the latest state to detect the virus in a commercial poultry flock, and on Friday it halted all poultry sales until limit the further spread of the disease. Across the country, egg prices are skyrocketing – if you can even find them at your local grocery store.
The ongoing animal epidemic also led to this at least 67 cases of bird flu in humanswith all but one causing subtle disease. Earlier this month in December, one person in Louisiana died after being hospitalized with severe bird flu. This is the first recorded death in the country attributed to the H5N1 virus.
The United States has already licensed three H5N1 vaccines for humans, but they are not commercially available. The government has purchased millions of doses for the national stockpile in case they are needed. But even as the epidemic spread, federal health officials under President Joe Biden were hesitant to deploy them. Experts say the decision is risk-based and that the risk of H5N1 infection remains low at this time. Rolling out the vaccine to farmworkers and others at higher risk of infection would be a more targeted tactic, but even that may be premature. Now, with a change in federal health leadership imminent as President Donald Trump begins his second term, the decision rests with the fresh administration.
“At this point, from the standpoint of severity and ease of transmission, it doesn’t seem necessary to develop a vaccine to protect people,” says William Schaffner, a physician and professor of preventive medicine at Vanderbilt University in Tennessee.
So far, no human-to-human spread of the H5N1 virus has been identified, but health officials are monitoring the virus for any genetic changes that would make it more likely to spread between people. Most bird flu infections result from animal exposure. Of the 67 known human cases in the U.S., 40 have been linked to unwell dairy cattle and 23 to poultry farms and slaughter. In the remaining four cases, the exact source is unknown.
In the US, human cases have been subtle, with many causing only conjunctivitis. In some cases, people experienced subtle respiratory symptoms. Apart from the Louisiana patient, all of the people who tested positive for H5N1 recovered quickly and did not require hospitalization. Historically, H5N1 has been fatal in about 50 percent of cases. Since 2003, there have been a total of 954 cases of human H5N1 virus have been reported to the World Health Organization, and about half of them died. Egypt, Indonesia, Vietnam, Cambodia and China reported the highest number of human deaths from bird flu.
These numbers come with a few caveats. First, many of these deaths occurred in places where people live very close to diseased poultry. “Under the circumstances, it is believed that they probably received a very large dose of the virus,” Schaffner says.
Moreover, the mortality rate – the percentage of infected people who die from the disease – only includes known cases, and some cases of the H5N1 virus undoubtedly go undetected, in part because the symptoms of bird flu are similar to those of other respiratory viruses. In the U.S., language barriers among farmworkers, lack of testing and workers’ reluctance to report illness also play a role. “We probably miss more cases than we detect, and we are much more likely to detect a serious case,” says Shira Doron, director of infection control at Tufts Medicine in Boston and a hospital epidemiologist at Tufts Medical Center.