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Why the H5N1 bird flu is keeping the CDC’s top flu scientist awake – STAT




Why the H5N1 bird flu is keeping the CDC's top flu scientist awake - STAT

VIvien Dugan doesn’t sleep much these days.

Dugan, director of the Centers for Disease Control and Prevention’s influenza division, leads the team of CDC scientists working with partners — in the U.S. Department of Agriculture, the Food and Drug Administration and state and local health departments — to respond to the outbreak of H5N1 bird flu in dairy cattle.

The response has been brutal since the USDA announced on March 25 that a strange disease that had affected milk production in some herds since early this year was caused by bird flu. Since then, 36 herds in nine states have tested positive for the virus.

Assessing the risk of the situation and communicating it to the public is a balancing act, she admitted. While workers on affected dairy farms are exposed to the virus — one has tested positive so far — the risk to the individual American elsewhere is currently low. Demetre Daskalakis, director of CDC’s National Center for Immunization and Respiratory Diseases — where the flu unit is housed — said Wednesday that 25 people have been tested for H5N1 in the context of this outbreak, and that more than 100 people have been monitored for symptoms because they were thought to have that they had been exposed.

The responding agencies have years of experience working with poultry farmers, who have been plagued by this virus in recent years. But for the agencies, moving into livestock was like entering a new country. Dairy farmers have no experience with bird flu. Many farmers and farm workers were not eager to cooperate with the authorities.

In an ideal world, blood samples from people who had contact with the infected farm worker would have been examined to look for H5N1 antibodies to see if he had transmitted the virus to anyone, a technique called a serological survey. But Dugan said she believes the people involved would not consent.

STAT asked Dugan about the work the CDC is doing, the complaints from scientists around the world about the amount of information the United States has shared, and where the needle on its H5N1 risk gauge is right now. As we spoke, a colorful image of a rooster was visible on a dresser behind her – fitting backdrop for a flu researcher.

The interview has been edited for length and clarity.

The number of people tested and/or monitored seems impossibly low, given the number of workers who would have been exposed to the infected animals. How hard is the US looking for business?

Vivien Dugan, director of the CDC’s influenza division. CDC

We had a team pretty much ready to go six weeks ago when this first really started appearing on our radar. But this is not the average response situation for poultry workers. These are dairy farms. The poultry sector and the poultry industry have actually been responding to H5 over the last two and a half years. More than 8,000 people have been checked for symptoms in the H5 poultry room. It’s a very different environment when we talk about dairy cattle and dairy farms.

That said, we’re really thinking about how we would do the research that we would normally do for a new flu case – where they are all nationally notifiable infections in humans – in a way that makes scientific and epidemiological sense.

The states are really focusing on that and really trying to get as much information as possible. So it’s actually more in that local space. We support them in this. Some states have been able to contact workers directly and conduct active surveillance. Others, of course, were not as successful.

So it is a work in progress. We have a number of potential locations that we are trying to do more with to get the logistics in order. But no studies have been completed yet.

No studies have been completed yet. Have investigations been started?

That’s probably a good question for some of the affected states. We don’t want to get ahead of them on the work they’re doing where we don’t have all the details.

It sounds like your team, which was ready to go, didn’t go. And from what you’re telling me, it seems like CDC is very much taking a backseat in this case. That it’s the states or local authorities that are running this.

They have the authority, right? CDC does not have the authority to enter any state. We need an invitation from the public health department.

Are there any states that have invited CDC?

No. Not official yet. We talk to these partners, if not once a day, more than that.

There are many sensitivities. There are many things that we as public health officials may not be aware of when we think about dairy farms. We are used to working with poultry companies and poultry workers, where they cull all the birds. These cows are not culled. So it’s a very different space.

We are working very closely with the state’s public health partners where they may be able to lead an investigation. And we would support in the background. Sometimes we don’t have to deploy a team; we can equip our national public health partners to collect the information and work with them to do that.

There has been a single human case in Texas. Has anyone performed serological testing on that person? That would be an obvious starting point, wouldn’t it?

I don’t know if permission was given for that. You have to have people’s permission to follow up. It was certainly something that was on our radar for what we would like and ask for, but as far as I know no serology was performed. (A report on the case published Friday in the New England Journal of Medicine confirmed Dugan’s belief. The infected person and his contacts would not agree to have blood drawn.)

The scientific world has been looking at H5 for a long time. CDC has been very involved in that. And whenever there have been unusual outbreaks, this country has always pushed for rapid case finding and data sharing.

I’m hearing from people outside the United States that when the shoe is on the other foot, when the outbreak is here, they are not seeing the information sharing they would hope for, or even evidence of the work that is critical to figuring out whether whether or not this can be seeded into the human population is currently happening. Do you have a response to that?

It’s a complicated situation as far as [there are] new partners and new individuals and a different group of farm workers. We are doing everything we can and thinking about messaging, multilingual messaging, communication, PPE [personal protective equipment], biosecurity on farms, and working with USDA to truly protect workers. That is absolutely one of our highest priorities, and it always is.

But we’re also really thinking about in the medium and longer term what it could mean that a virus could circulate within a new mammalian host. I don’t think anyone can really predict what might happen, but we know for sure that flu viruses change. And we don’t want to give the virus that chance, if we can avoid it.

By the way, I think you should add something to your sculpture collection. The chicken needs a cow.


When it comes to data sharing, we try to be as open and transparent as possible with the data we have. I think we do that in the “Spotlights‘ that we release every Friday. We have the Texas human virus sequence out as quickly as possible.

So I think we try to do that as much as possible. We can always do more. But a big part of this is our partnerships with the states. We introduce ourselves to them. We need to get behind the scenes and let them talk about what’s happening in their state.

May I ask for your personal opinion about the risk here? If this virus enters the cow population and develops in cows, what do you think this will do to the human risk from H5N1?

[Dugan grimaced.] I think it would definitely have an impact on the risk. Our current assessment of the risk to general public health is low. That could change. And so I think we remain very vigilant – or even more vigilant in this area.

These viruses change. If this were to be seeded into cows and a virus endemic to cows, this risk to humans would certainly increase.

And certainly our pandemic planning [operation] has really thought about this and tried to be as vigilant as we can right now, to understand not only the current risk, but also the future risk, so that we are as prepared as possible.

But the risk can be quite high.

You said you still think the risk is low. But 15 years ago this spring, the CDC was notified of two California children who had tested positive for swine flu and had had no contact with pigs or each other. Before April 17, 2009, the risk of a swine flu pandemic seemed quite low. And then CDC got those two samples, and everything changed very quickly. Are you thinking about that?

Well. That’s probably why I’m not sleeping much right now.

I think the threat of a pandemic is always lurking in the flu world. The way Dan Jernigan [Dugan’s predecessor] what has always defined public health for me is that it is an art form. There is a balance you have to find. There is a difference between the pandemic risk and the immediate risk right now. And so I think that’s what we’re trying to get across to the average person walking around and living their life. The risk to them is low.

But you’re right. It could absolutely change.