The Biden administration is monitoring what experts say is the deadliest outbreak of bird flu the US has ever seen, and officials are considering a “gamut of options” for how to respond.
The outbreak is not currently considered a serious threat to human health, according to the US Centers for Disease Control and Prevention.
Worldwide, there have been only a few cases of bird flu in humans, mostly in people who have had direct contact with infected birds or surfaces contaminated with their droppings. There was one human case last year in the United States, a man from Colorado who became ill after killing infected birds. He was isolated and given an antiviral.
More than 860 total cases of bird flu have been reported in humans in 19 countries since 2003, and more than half of those cases have been fatal, according to the CDC.
World Health Organization director-general Tedros Adhanom Ghebreyesus said in February that the risk to humans remains low. However, given the large number of infected birds, he added, “we cannot assume that this will remain the case.”
There have been 6,356 cases in wild birds in all 50 states, according to the CDC, but there are likely many more. In 47 states, there were multiple outbreaks among poultry, involving more than 58.6 million birds. It has also appeared in non-commercial backyard swarms, according to the US Department of Agriculture.
The disease has also appeared in other animals in the US, including bears, foxes, raccoons, possums, mountain lions, bobcats and even a bottlenose dolphin. As the virus moves through mammals, it becomes more likely to mutate and spread more easily to humans.
The CDC is able to track the virus in communities through the labs it uses to track more typical flu viruses. The agency also told CNN that it is also investigating whether manufacturers might want to do commercial testing for these viruses. more widely available.
The Biden administration said it is also closely monitoring the situation.
“As part of the administration’s focus on addressing any infectious disease with urgency and preparedness, we continue to monitor the bird flu outbreak. There are a number of options that the United States routinely considers when there is an outbreak that could affect the safety and security of the United States’ food supply,” a National Security Council official told CNN.
“Right now, we’re focused on promoting and strengthening high-impact biosecurity practices and processes.”
Biosecurity procedures usually include improved decontamination practices for people working with birds. In November, the CDC recommended that people interacting with birds that appear sick—even in backyard flocks—should wear disposable gloves, boots, eye protection and an N95 respirator or face mask.
“CDC continues to take any infectious disease threat seriously and assesses the current risk of bird flu to humans as very low. The Department of Agriculture continues to respond quickly whenever the virus is detected in bird populations,” the National Safety Council official said.
The CDC says the risk assessment tool it uses to understand a virus’ potential for pandemic risk has determined that if these H5N1 viruses mutated into a version that could spread easily and effectively to humans, the pandemic risk is “moderate” and the public health impact of such an event would also be of moderate severity.
“That’s why it’s so important that both the public health side and the animal health side take precautions to limit exposure between animal species and between animals and humans, and thus limit the chances of some sort of viral reassortment event that can to allow these viruses to infect people easily and spread easily between people,” the agency said in an email to CNN.
General precautions include limiting animal outbreaks and limiting public exposure. This includes avoiding close contact with sick birds, fully cooking poultry and not eating raw eggs.
Another precaution is to arrange for a vaccine, just in case, and efforts are underway.
Scott Hensley, a professor of microbiology at the University of Pennsylvania, and his colleagues are working on a vaccine candidate that could be used in humans if the virus began to circulate among people.
“We think the vaccine will elicit very high levels of neutralizing antibodies against this particular strain because it’s basically a perfect match for what’s out there now,” Hensley said.
The vaccine appears to be working well in the lab, he said, and researchers plan to test it in chickens this spring.
The CDC says it recently produced a candidate vaccine virus, a flu virus that manufacturers can use to make a vaccine, that is nearly identical to a viral protein found in birds and mammals. It could be used to produce a vaccine for humans “if needed.”
“Such a vaccine would be expected to provide good protection against circulating H5N1 viruses,” the CDC said. The agency said it has shared it with vaccine makers.
For years, the Southeast Poultry Research Laboratory, a division of the US Department of Agriculture, has also been working on a vaccine for possible emergency use in animals. There may be an advantage to vaccinating poultry to reduce the chances of the virus mutating.
Vaccinating poultry against bird flu “isn’t something that’s really done in our country, but I think it’s time to think about it for sure,” Hensley said.
Farm animals, including birds, are already vaccinated against other diseases. Chickens, for example, are routinely vaccinated against Marek’s disease, which is caused by a herpes virus. They have also been vaccinated against Newcastle disease, a respiratory disease. infectious bronchitis; and acute necrotizing procoilitis, a viral disease that affects the immune system.
Bird flu may one day be added to that list, according to a USDA spokesperson.
“Not to let up in the fight against (highly pathogenic avian influenza), the USDA continues to investigate vaccine options that can protect poultry against this persistent threat,” the spokesperson told CNN.
Vaccination, however, is not the first choice.
“From vaccine development to production schedules to swarming, there are many factors that make implementing a vaccine strategy a challenge, and it would take time to deliver an effective vaccine,” the USDA said.
So first and foremost, “we continue collaborative efforts with poultry farmers and companies to educate, train and implement comprehensive biosecurity measures. Biosecurity is the best and most prudent approach we have to mitigate the impact of disease today.”