The bird flu virus circulating among cows, poultry and wild birds isn't yet a threat to the general public, but experts say if and when that will change is impossible to predict — and that if things do get bad, the U.S. is probably underprepared.

Why it matters: As we learned during COVID, pandemics have world-altering consequences. Staying ahead of them is key — but that's not really what the public is in the mood for in the aftermath of the last pandemic.

• The first bird flu fatality isn't indicative of an imminent crisis. But the more chances the virus is given to spread and mutate, the more likely it evolves into something capable of sparking a pandemic.
• "It could become a pandemic tomorrow, it could never become a pandemic. The reality is we just don't know," said Angela Rasmussen, a virologist at the Vaccine and Infectious Disease Organization at the University of Saskatchewan.

Where it stands: The bird flu virus, scientifically known as H5N1, has been circulating among U.S. dairy cows since at least March. The CDC says the current public health risk is "low."

• All but three of the 66 confirmed human cases last year were exposed through commercial agriculture, and the person in Louisiana who died this week contracted the virus from infected birds in a backyard flock.
• "The risk today for the average person is low. That said, that does not mean it will stay that way," Nirav Shah, principal deputy director of the CDC, told Axios.

Context: Crucially, there have been no known cases of human-to-human transmission, and one death out of 66 confirmed cases is a much lower fatality rate than is generally feared with a H5N1 pandemic.

• But animal transmission is still going strong. The CDC says there is an "ongoing multistate outbreak" among dairy cattle, "sporadic outbreaks" among poultry flocks and "widespread" presence of the virus among wild birds.

Yes, but: The CDC issued a report in August that determined the current virus presents a "moderate" future pandemic risk.

• That's not significantly out of line with previous influenza viruses, Shah said.
• "This virus is not a wimp. We are not trifling with it, we're taking it very seriously. But history matters."

The big picture: Influenza is an "incredibly unpredictable" virus, Rasmussen said.

• It can evolve through both mutations and through essentially swapping characteristics with other flu viruses if someone is infected with both at the same time.
• That makes rampant bird flu spread among animals particularly risky during flu season for humans.
• "It's like shuffling two decks of cards together," Rasmussen said. "Sometimes that combination in ways we can't predict will lead to a virus that is basically able to take off in the human population."

"It's essentially like lottery tickets. If you buy one lottery ticket, your chances are low of winning the lottery. If you buy 10,000, your chances go up," said Andrew Pekosz, a professor at the Johns Hopkins Bloomberg School of Public Health.

• "And as long as we allow this virus to infect mammals and humans, it's like we're giving the virus more lottery tickets, and eventually they're going to win."

Between the lines: The million-dollar question is, of course, how dangerous the virus would be if it does evolve into something that can spread between people.

• H5N1 viruses that have infected people in the past have had mortality rates around 50% — a terrifying number with enormous consequences for modern civilization, should a virus that lethal become a pandemic.
• Clearly, the mortality rate in humans over the last year has been nowhere near 50% — it's 1 in 66 for now, and that's only the known cases. And the 50% number could be skewed if many mild cases went undetected during previous outbreaks.
• But how the virus will change is completely unpredictable, and knowing how bad a bird flu pandemic would be is dependent on the details of those changes.

The bottom line: "To me, the take-home message here is that this virus may be less lethal than previous H5N1s, we don't know, but there are so many variables that contribute to this, we should not assume this is a safe or mild virus," Rasmussen said. "Clearly the patient in Louisiana shows this virus can kill people."

The bad news is that some experts fear the U.S. is behind and unprepared for an influenza pandemic, should the bird flu ever become one.

The big picture: For all the talk of lessons learned post-COVID, some of them aren't being applied now, some say.

• And COVID's politicization of public health has not only instilled a fear of overreacting but could also seriously handcuff the government's response in an emergency.

Reality check: If a pandemic happens, it will happen pretty fast.

• "We won't have a lot of time to shift from 3 miles an hour to 300 miles an hour," said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
• That means preparation — even if it turns out to be unneeded — is crucial.
• "We've seen this before without it moving to a pandemic. Having said that ... I'm very concerned about how unprepared we are for the next influenza pandemic," Osterholm added.

Yes, but: The CDC's Shah said that on many measures, "we are actually ahead of where we'd need to be in terms of preparedness."

Others are critical of the response so far.

• "The Biden administration has been mishandling the outbreak in cattle for months, increasing the possibility of a dangerous, wider spread," former FDA commissioner and Pfizer board member Scott Gottlieb wrote in the Washington Post with Luciana Borio, a former director for medical and biodefense preparedness policy at the National Security Council.
• Numerous sources pointed to the inherent tension that has existed between protecting agricultural interests and taking a precautionary human health approach.
• "Multiple players have sought to downplay the threat: the dairy industry fears further economic setbacks, state leaders are wary of federal intervention, and the Biden administration did not want to aggravate relations during the 2024 election cycle," the Center for Strategic and International Studies wrote in a report last month.

The latest: The Biden administration recently announced $306 million in funding for the bird flu response, including money for preparedness programs.

• The U.S. is currently ramping up its supply of bird flu vaccines, and the Biden administration has also provided funding for vaccine manufacturing to drug companies.

Vaccines would obviously be an enormously important tool should a pandemic happen. But here's the catch: There's no guarantee that the vaccines in existence today would work well against whatever causes the pandemic.

• "Vaccine-wise, we've got the number of doses we have to 10 million, but we don't know that vaccine we have will protect against the virus that would emerge," Osterholm said.
• And there's no telling how many Americans would take a new flu vaccine, given the high post-COVID levels of vaccine hesitancy.

The other side: Some experts — including the CDC — say we're actually not horribly off, relatively.

• "If you make the comparison to COVID, we are in a much better place when it comes to H5N1 than we were with COVID," Johns Hopkins' Pekosz said.
• That's because it's a known virus — scientists have a good idea how it spreads, drug companies know how to make flu vaccines, we have antivirals that work (for now) and we have diagnostic tests that recognize bird flu, he said.
• "Influenza H5 is the foe we know. COVID was the foe we didn't know anything about," Shah said.

What we're watching: In 10 days, this is the Trump administration's problem, and many of the people he's tapped for top health care positions have been huge critics of the COVID-19 response.

• How that translates into any kind of bird flu pandemic prep will be an early test of the new administration.
• "Trump now finds himself presiding over a nation weary of pandemic-era strictures," Borio and Gottlieb write.
• "His new efforts to mitigate the risk from bird flu must do more than condemn past shortcomings during the coronavirus pandemic; it should demonstrate that public health agencies can safeguard Americans while ensuring that the measures they take don't place undue burdens on everyday life."