Could bird flu strain the US public health system as seasonal influenza ramps up?

(NEW YORK) -- As seasonal influenza ramps up, and with bird flu continuing to circulate, some public health experts are worried there may be a strain on the public health system.

Since the bird flu outbreak began earlier this year connected to dairy cows and poultry, there have been 55 human cases reported in the U.S., according to the Centers for Disease Control and Prevention (CDC). This includes a child in California, who was confirmed on Friday by the agency to be the first pediatric case linked to the outbreak.

There is currently no evidence of person-to-person transmission of bird flu and the risk to the general public is low, federal health officials say. But with millions of seasonal flu infections around the corner, there is some concern about additional stress on how public health surveillance systems will track the virus.

"I think it does add a layer of stress, at least in the public health planning part of things, because we have to think about what resources would be necessary were we to have a significant outbreak of bird flu," Dr. Tony Moody, a professor of pediatrics and infectious diseases specialist at Duke University, told ABC News.

Bird flu and seasonal flu at the same time

Currently, respiratory virus activity is low in the U.S., but the country is on the brink of entering traditional flu season.

Dr. Otto Yang, a professor of medicine and microbiology, immunology and molecular genetics at the David Geffen School of Medicine at the University of California, Los Angeles, said the flu season earlier this year in the Southern Hemisphere looked typical so the same can be expected for the Northern Hemisphere.

Countries in the Southern Hemisphere experience their flu season before countries in the Northern Hemisphere. This often provides a glimpse as to what the upcoming flu season may potentially look like for the Northern Hemisphere, though it is not fully predictive of what may occur in each individual country.

"It looks like everything so far points to a fairly typical flu season in terms of the numbers, not [an] especially severe flu season, but not one especially mild either," he told ABC News.

So far, all bird flu cases in humans in the U.S. have been mild and patients have all recovered after receiving antiviral medication. Almost all confirmed cases have had direct contact with infected livestock.

Yang said he doesn't see bird flu putting a major strain on the health system right now, but there are unknown factors such as whether COVID-19 or RSV will lead to a higher number of cases than normal.

Moody added that health systems have conversations every year about respiratory virus season regarding whether there are enough beds, enough staff and enough equipment to treat sick patients, and that unknown factors always present a threat.

"That's what we would be thinking about, is, what can we do to try to blunt that as much as possible, because it's not so much that the public health system can't absorb it," he said. "They just can't absorb everything all at once."

Testing for bird flu

With flu season expected to start ramping up in the coming weeks, it may be increasingly difficult to differentiate bird flu from seasonal flu without more extensive testing, experts say.

"The reality is, we want to be ahead of a problem. There's a surveillance challenge that was easier in the summer because we didn't have seasonal flu cycling," said Dr. John Brownstein, an epidemiologist and chief innovation officer at Boston Children's Hospital and an ABC News medical contributor. "As we enter flu season, we're going to have a respiratory mix that includes flu and may include cases of avian, and it'll be an even greater needle in the haystack."

Right now, a PCR test, which checks for genetic material, is needed to detect a novel flu virus in a patient. More than 60,000 tests have been completed by public health labs to detect any presence of bird flu since February of this year, according to the CDC.

Tests are sent to public health labs if there is suspicion of bird flu exposure from a clinician or a sample was submitted for surveillance purposes. Health care systems send in a quantity of flu samples to public health labs for additional testing to help detect any new bird flu cases, which is how a case in Missouri was initially identified.

"We're doing some opportunistic sampling of cases that would get additional sequencing. [Our hospital] is sending five samples per week to state labs that would ultimately get deeper identification for bird flu," Brownstein said.

The nation's flu surveillance systems "are built to be able to detect novel flu infections even during peak flu season" the CDC told ABC News in a statement in part. "The level of testing performed is designed to scale with increases in seasonal flu activity so that we're casting a wider net and maintaining the ability to detect rare infections with novel influenza viruses."

Other surveillance methods like emergency department trends and wastewater data may become less reliable as seasonal flu ramps up, Brownstein said.

"Patients that have access to rapid tests at home also aren't necessarily collected and connected to surveillance systems" he added.

Risk of recombination

Questions have swirled about whether or not bird flu and seasonal influenza could form a recombinant virus, meaning a combination of the two.

There is currently no evidence that this has happened and, although it is possible for either virus to mutate with each new case, experts believe this is unlikely considering bird flu is not yet showing evidence of person-to-person transmission.

"It certainly is possible, but generally you get recombination when you have hosts where both strains can get in easily, and at the moment the bird flu strain is not traveling human to human, and so very, very few humans are infected with it," Yang said. "It's been a handful of cases, so the risk is really tiny."

Moody said so-called "recombination events" do happen, with people becoming infected with multiple viruses at the same time or multiple strains of a virus. However, most of the time, they are "failures," he said.

"That's an important thing to understand, these recombination events are happening all the time and, most of the time, it doesn't go anywhere," Moody said. "Very, very rarely it does, and then that becomes a possibility for transmission"

How to best protect yourself

Moody and Yang say they both recommend that people receive the flu shot. Flu vaccines are currently available for everyone six months and older, according to the CDC.

In the last flu season prior to the COVID-19 pandemic, flu vaccination prevented an estimated 7 million illnesses, 3 million medical?visits, 100,000 hospitalizations, and 7,000 deaths in the U.S., the CDC said.

The seasonal flu vaccine does not protect against bird flu, but it can reduce the risk of human influenza viruses, and therefore lower the risk of co-infection.

"Is there the potential for some cross-benefit for the avian flu? There may be. It's hard to say, because, of course, these viruses are distinct from one another," Moody said.

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