Just as avian (bird) flu continues to spread among birds and other animals, it’s also continuing to move through the human population in the United States.
As of early March, human cases of avian influenza A(H5N1) have been reported in several states across the U.S., including Oregon, California, Colorado, Louisiana, Iowa, Wisconsin, Michigan, Ohio, and Wyoming. Recently, Wyoming reported its first human case of H5N1, bringing the total to 70 confirmed cases across 13 states. The Wyoming case involved an older woman who was hospitalized, marking the third avian flu-related hospitalization in the U.S. Ohio also recently reported a fourth hospitalization due to avian flu; the person was treated and released. Tragically, the first confirmed bird flu death was reported in Louisiana in January.
It's not just humans who are affected by this outbreak. According to the Centers for Disease Control and Prevention (CDC), as of March 5, more than 978 dairy herds in 17 states have been affected by H5N1. A new strain was detected in Nevada in early February, indicating that the virus may continue to circulate and potentially become endemic.
There is also evidence of undetected H5N1 bird flu infections in both humans and animals. A study published in MMWR on February 13 revealed that among 150 veterinarians who work with beef cattle or dairy cows in 46 states, blood tests showed that three of them (2%) had antibodies indicating a recent asymptomatic H5N1 infection. This suggests possible undetected spread in both humans and animals.
Government actions to address avian flu
According to the U.S. Department of Agriculture (USDA), 83% of avian flu cases are caused by transmission from wild birds. The USDA has announced several new approaches to address avian flu, including safety measures for farms to help them minimize flu cases due to wild bird transmission. The federal agency also plans to increase relief aid to farmers whose farms have been affected by bird flu, with new programs under consideration to help them speed the repopulation of their flocks.
Avian flu vaccine development
While getting a seasonal flu vaccine is recommended, especially for those at higher risk of exposure to infected animals, it does not provide direct protection against bird flu. While the risk to the general public remains low, efforts are underway to develop and stockpile vaccines for avian flu in case of a national health emergency.
The USDA recently gave conditional approval to an updated avian flu vaccine for poultry. In addition, the FDA has approved three bird flu vaccines for use in humans, which have been added to the national stockpile. This stockpile includes vaccines that are not currently available to the general public, but are ready to be rolled out in a health emergency. The stockpile also contains raw materials to create enough vaccine doses for critical care workers and people at high risk of infection. Aside from this, several vaccine manufacturers are also developing or investigating mRNA vaccine options for bird flu.
While antiviral treatments approved for seasonal flu are also effective in treating avian flu, antiviral treatments are also being developed specifically for bird flu.
Concern over co-infection with avian flu and seasonal flu
With both seasonal flu and avian flu both in circulation, there may be a potential for a person to become infected with seasonal flu and bird flu simultaneously. This could open the door to viral reassortment, in which each flu virus swaps genetic material.
Viral reassortment could result in the evolution of more transmissible or severe flu strains. However, getting vaccinated against seasonal flu could reduce opportunities for bird flu and human flu viruses to mix and potentially create new strains.
If you have concerns about your risk of exposure to avian flu or general questions about seasonal influenza, talk to your healthcare provider. They can provide personalized guidance based on your individual circumstances.
