Discussing the Scary Word ‘Pandemic’
Public Health prof David Ozonoff is keeping cool, but yes, he’s worried
As swine flu continues to spread, the World Health Organization yesterday raised its alert level to Phase 4, indicating that “the likelihood of a pandemic has increased, but not that a pandemic is inevitable.” Phase 6 would mean that a global pandemic is under way.
Cases of swine flu (the H1N1 virus) are now confirmed in seven nations, although nearly all of the fatalities (about 150 as of yesterday afternoon) have been in Mexico, where the outbreak began and 1,600 cases have been reported. Still, governments and public health agencies around the globe have been taking precautions. On Monday, the U.S. State Department issued a travel advisory discouraging all nonessential travel to and from Mexico. Authorities at airports and border crossings are pulling aside travelers who show flu symptoms, subjecting them to tests and in some cases quarantine. Some countries are even banning pork products from the United States and Canada (although the virus, despite its name, isn’t spread by eating pork). Meanwhile, face masks and hand sanitizer have been flying off the shelves around the world.
This morning, two elementary school boys from Lowell, Massachusetts who had recently returned from a trip to Mexico were confirmed to have swine flu. They are the state’s first confirmed cases. About 200,000 doses of antiviral medications are being shipped to the state from the national stockpile.
All schools and universities in Mexico have been closed, canceling classes for 13 Boston University students currently in the Guadalajara Engineering Program until at least May 6 (just before finals were scheduled to take place). The study-abroad program officially ends on May 21. Joseph Finkhouse, director of institutional relations for BU International Programs, says that while BU is not encouraging students in Mexico to leave early, the University is offering to help those who wish to do so with travel agent services and by “working with them to make sure they’re not penalized academically.”
Reached by e-mail yesterday afternoon, several students in the Guadalajara program said that they were hoping to leave by week’s end. David McBride, director of Student Health Services, recommends that any students returning from Mexico not come to campus immediately, but “go directly home if at all possible” and remain there for a week to ensure that they are flu-free.
For insights into the swine flu scare, BU Today put some questions to epidemiologist David Ozonoff, a School of Public Health professor of environmental health.
BU Today: What is swine flu and is this the first time it’s been transmitted from human to human?
Ozonoff: Influenza is actually a group of viruses, and most infect animals. A few infect humans. Pigs get the flu and have for a long time. It has been true that there have been times when swine influenza has passed to human beings. In fact, the current strain, H1N1, was at one point thought to be the source of the 1918 pandemic. But more recent thinking is that it was likely the other way around — that we gave it to pigs in 1918, and that we likely got it from an avian source.
Pigs infected with H1N1 get sick, but it usually doesn’t pass to humans. Every year, the CDC gets a report of one or two cases of people infected with swine flu, but in recent years it’s been a couple or three. And there have been instances — in 1976 and 1988 — when there was a small outbreak with human-to-human transmission, but it burned itself out after one generation. The current situation seems to be different. It’s probable that several generations of this virus have been passed through human-to-human transmission, and it seems to be more easily transmissible.
Don’t thousands of people die every year from “normal” flu? Why is swine flu more dangerous?
So far, it seems to look a lot like seasonal influenza. But the difference is that it’s a type of flu to which humans have never, or very rarely, been exposed. We have a globe’s worth of immunologically naïve people. So any flu virus for which there’s basically no natural immune response is a recipe for a pandemic virus, which means a sustained human-to-human transmission happening in many places in the world. Now, "pandemic" is a scary word, because it’s applied to the 1918 flu, but it’s also applied to other things that aren’t as deadly, like head lice. It really isn’t a reflection of the severity of the disease, but that a lot of people are getting the disease in a lot of places at once.
How concerned should we be?
There are three broad possibilities. First, it could just burn itself out and go away and we’ll never see it again. That’s the best scenario. The other two scenarios are more likely. This could develop into a full-fledged pandemic, and we’d be off to the races. The third possibility has lots more uncertainty, but may be the most likely, and that is that we don’t have too much flu around in the summertime in the northern hemisphere. We don’t know where it goes really. But then it comes back again in late summer or early fall. That’s sort of what happened in 1918. There was a relatively mild outbreak in the spring, and when it poked its head up again in August, it was a full-fledged monster.
There’s an old saying about a lot of things: if you’ve seen one, you’ve seen them all. That’s not true with influenza. This is an incredibly unpredictable, tricky virus.
Our surge capacity, the reserve of staffed beds in our inpatient facilities, is less than it was a few decades ago, because we’ve been trying to cut the cost of health care by eliminating unnecessary hospitalization. The system is much more brittle today. In the summer, Boston’s city emergency rooms will be on diversion, meaning an ambulance will pull up and they’ll divert it to another place because they’re full. A bad flu overwhelms things; a pandemic would really be bad.
Why has the flu been so much more virulent in Mexico than in the United States and other countries?
The United States has done very aggressive and intensive case finding, including looking at people who haven’t been seeking medical care or who weren’t terribly ill. The Mexicans were looking only at seriously ill people in the hospital. So, the apparent difference in severity may be just that, apparent. As time goes on and there are more cases here and the Mexicans start looking at nonhospitalized people, we may find that the spectrum of illness is not very different.
How would you rate the response of global public health authorities to this outbreak?
I think the United States is doing quite well. Mexico did poorly. The WHO is tardy. But I think the pretty proactive and fairly aggressive stance that the CDC is taking is right.
What exactly is being done in the United States?
The federal government develops scientific information, sending a team to help Mexico collect data we need to figure out what’s going on. You’ll find all sorts of advice for ordinary people, for doctors, and for hospitals on the CDC Web site. It also has a strategic national stockpile of 50 million courses of antiviral medication. Over the weekend, 25 percent was released.
But most public health work in the United States is done at the state and local level. And we’re going to hear a lot about suspect cases. Most of them are probably not swine flu. State and local authorities are also involved in thinking ahead and planning.
Are we prepared if things get worse?
Because of the bird flu outbreak a few years ago, there’s been a lot of federally funded support and training. The reason we can figure out if a suspect case might be swine flu is because the federal government has trained about 140 public health labs across the country to subtype influenza. Specimens that can’t be subtyped at the state level go to the CDC. Without all that, we’d be in a pickle. First of all, we probably wouldn’t have discovered this thing. Second, if every suspect sample was sent to the CDC labs in Atlanta, they’d be overwhelmed.
This is where the question of “surge capacity” is important. What are public health authorities going to do if they are overwhelmed? They need to advise state and local authorities about school closures and the like, trying to decrease transmission by not having large public gatherings or shutting down nonessential public services, supervising the distribution of antivirals, and contingency planning for maintaining basic infrastructure and social services if there’s a lot of absenteeism.
Is the flu shot many got last fall going to do any good?
The news is not good about that. There appears to be very little cross-reactivity between the antibodies of that vaccine and this flu. People are very interested in whether there’s a new vaccine for swine flu, and the answer is, not yet. What the CDC has done is prepare a vaccine seed strain. They do that all the time. They’ve got this thing growing. But now they’re talking with the vaccine manufacturers, and there are some very big decisions. It’s not clear if there’s sufficient capacity to make enough vaccine for a new strain in addition to the regular seasonal flu vaccine, which has three strains. Each dose requires an egg for vaccine development. We’re talking about millions upon millions of pathogen-free eggs to do this. They have to talk to manufacturers about whether that’s even possible. You need more facilities. Either way, we’re talking about four months minimum.
Which precautions do you think are worth taking?
Hand and cough hygiene doesn’t cost much, and makes people feel better. I don’t know how much good it does, but it’s reasonable. Then there are the things described as personal responsibility, such as don’t go to work if you’re sick or don’t send your kid to school sick. But if I’m teaching a class and there are two classes left and a final exam and I don’t feel well, am I going to abandon the students? It’s one thing to say it’s my responsibility not to go to work sick, but another thing to understand what it’s like on the ground for people.
Chris Berdik can be reached at email@example.com Comments