Avian Influenza: Prevention, Progress, and Public Health Priorities

Author(s):

To learn more about the recent bird flu outbreaks, we spoke with Asha Shah, MD, director of infectious diseases and epidemiologist at Stamford Hospital.

In this interview with Asha Shah, MD, director of infectious diseases and epidemiologist at Stamford Hospital, we examines the evolution and transmission dynamics of H5N1 avian influenza, emphasizing that although human-to-human transmission remains limited, the virus’s potential to adapt requires ongoing surveillance. We also discuss the efficacy of antivirals like Tamiflu for treatment of season flu, lessons from past outbreaks that inform current containment strategies, and the role of vaccine development in preparedness. Additionally, the conversation addresses the importance of preventive measures, public compliance, and dispelling misinformation to mitigate risks, especially during overlapping seasonal respiratory virus surges.

And if you would like to learn more about avian influenza, please explore these valuable resources:

This transcript has been lightly edited for clarity.

Asha Shah, MD | Image Credit: © Stamford Hospital

The American Journal of Managed Care^® (AJMC^®): How do the avian influenza viruses evolve to become transmissible from animal to human and human to human?

Shah: This is a highly pathogenic avian influenza, H5N1—what people are commonly referring to as the bird flu. Influenza, in general, small changes in the genetic structure of the virus can lead to the emergence of new subvariants, and variants and strains, kind of similar to what we see with coronavirus and with COVID-19, how we see new subvariants developing as the virus evolves with time. This can occur in humans, and it can also occur in animals. What we're seeing now is a large multistate outbreak in animals due to H5N1.

AJMC: Are there lessons from past outbreaks that have informed current containment strategies, and will the current outbreak inform strategies going forward?

Shah: You would hope. I'm more thinking about this in terms of our response to the COVID-19 pandemic. You would think, “Okay, that was a very once-in-a-lifetime thing” hopefully, and what we learned is rapid development of vaccines and therapeutics testing. You can tell that that is already occurring. For example, they've been looking at a vaccine for H5N1 for some time. We know therapeutics that work for H5N1, and the CDC and state health departments are really on top of trying to encourage more rapid detection of H5N1 when a nontypeable influenza A comes up on routine testing.

So, did we learn something? Are we learning something? Yes. I think it's a bigger picture about the world of public health in general, on how we prioritize these things. I've noticed that there is a little bit more of kind of upfront attention to this, because I think folks are kind of like, “Oh my god, is this going to be the next pandemic?” Because we recently just went through that.

AJMC: How effective are the existing antivirals against the different strains of avian influenza?

Shah: The recommended treatment for H5N1 is the same treatment for the regular influenza that we see, for the seasonal influenza we're seeing that does transmit from human to human. That's with Tamiflu (oseltamivir). Based on observational studies, it is effective for H5N1 as well. The treatment course for an outpatient is 5 days. That is the recommended treatment for outpatients with H5N1. There are some cases where we would extend the course to 10 days, and that would be in patients who are hospitalized, severely ill, or have immunocompromising conditions,

AJMC: How do the transmission dynamics differ between avian influenza and seasonal influenza?

Shah: The key point is that we are not seeing sustained human-to-human transmission with this strain of avian influenza, whereas with the seasonal influenza, there is sustained human-to-human transmission. And I think that is what's keeping avian influenza in check right now, because the main transmission is occurring between animal and human, but not human to human. I don't know for sure, and I don't if anyone knows for sure, but I'm assuming that's just related to the structure of the virus and the type of variant that it is. It doesn't stick human to human.

AJMC: There's been talk very recently of a quad-demic: flu, respiratory syncytial virus (RSV), COVID-19, and norovirus have all been surging as of late. In addition to the bird flu outbreak, why are these surges overlapping now?

Shah: This is not new. I know the media really tries to make this story every winter, but even prior to the pandemic, this is respiratory virus season. We are in the thick of it, so the trends that we're seeing in RSV, flu, COVID-19, and norovirus are not alarming to infectious disease specialists because these are the normal viruses that circulate around this time of year. Usually, RSV rises first, and then influenza tends to pick up just prior to and after the holidays. COVID-19 is a little bit of a wild card, but always kind of circulates in the background, whether it's the summer or the winter. Norovirus is also a common viral gastroenteritis. We see it in the wintertime.

I think what's happening is that since the pandemic, people have become hyperaware of what virus they have. They’re like, ”Oh, you need to get tested.” But if you're a normal immunocompetent patient, you may not need to know what virus you have. There's a lot of testing happening. I think with the pandemic, when people were just lining up to get COVID tested, I think that's the new norm now. We're getting a lot of data.

The quad-demic term, I don't think that's really accurate. It's endemic. These are endemic viruses. These are just seasonal trends that we typically see.

AJMC: How do public perceptions of avian influenza influence compliance with preventive measures such as typical vaccines or biosecurity guidelines?

Shah: The main public health recommendations for prevention of bird flu are for those individuals that are potentially exposed to these animals. The recommendation is to wear personal protective equipment and to get the seasonal flu vaccine. Even though we know that doesn't protect against avian influenza, it is still a recommendation, because coinfection with avian influenza and seasonal flu can make people quite sick. Also, hand washing and all that stuff. It's unclear to me if that's having an effect. I don't believe Connecticut is on the list of states where livestock have been affected. We haven't seen any potential exposures, we haven't seen any cases here to date. But there is a lot of information out there, and I would hope that in these agricultural communities that there's education going out on how people can stay protected.

AJMC: Are there any misconceptions or misinformation about bird flu that you would like to dispel?

Shah: First of all, eating meat and drinking milk is safe. That's a common question that we get. As long as the milk is pasteurized, that's safe. I think the other thing to remind people of is that the current public health threat is low, because there's some people who think this may be the next pandemic. It is a problem, but again, the key here is that we're not seeing sustained human-to-human transmission, and that's something that I think is important to highlight. Could that change? Yes, but that's why these public health systems are in place: to do contact tracing and all of these things with each case to monitor possible members to ensure that's not something that's being observed in these patients.

AJMC: What is the most important thing you would like the public to know, or how can you reassure them about avian influenza?

Shah: The most important are reassurance and vigilance. In general, it's respiratory virus season, so get vaccinated, wash your hands, have respiratory etiquette, stay home when you're sick—all of those basic public health prevention measures I think are really important, whether you're talking about avian influenza or seasonal influenza or RSV or COVID or norovirus. All of those things are still relevant.

We're keeping a close eye on this and seeing if there's any red flag signs that we need to change anything. The key is if we start to see sustained human-to-human transmission, if we're starting to see that household contacts of cases are testing positive without any other traditional epidemiological factors, like exposure to infected animals. That would be a concerning trend that would have us saying, “Oh no, this is changing.”