In a previous post I linked to a short note about the early days of the AIDS epidemic.

It's well-written, but I'd like to address a side issue that rubs me the wrong way. The author touches on it in her opening sentence:

At a time when the mere threat of avian flu or SARS can set off a coast-to-coast panic—and prompt the federal government to draw up contingency plans and stockpile medicines—it's hard to imagine that the national response to the emergence of AIDS ranged from indifference to hostility.

This is an echo of a certain resentful tone that I've noticed before when people affected by AIDS discuss the public health response to other diseases. One of the commenters makes it a little clearer:

So interesting that you point that out, everyone so worried about chickens. No one cared when so many of my friends were dying each in there own individual horrible way.

Obviously, I'm not condoning indifference and outright hostility against AIDS victims. The public health system responded poorly to the early days of the AIDS epidemic. One of the things that struck me while reading Randy Shilts's riveting And the Band Played On is the way public health officials uttered a depressing progression of statements about the emerging crisis:

• It's not a priority because only 5 people have died.
• It's not a priority because only 20 people have died.
• It's not a priority because only 100 people have died.
• It's not a priority because only 1000 people have died.

Of course, the best time to try to stop an infectious disease is before it infects a whole lot of people. It's as if these policy makers didn't understand the implications of the word contagious.

Actually, I think there's a grain of truth to that. I'm pretty sure that much of the foot-dragging in the early years was due to routine bureaucratic inertia. The kinds of people that climb to the tops of government agencies by winning budget battles and currying favor with political power brokers are not necessarily the kinds of people you want in charge when something terrible happens. We had another reminder of this when hurricane Katrina struck New Orleans.

Still, I have to believe that a big part of the problem responding to AIDS was due to dislike for the types of people the disease was infecting. When people affected by AIDS get angry about that, I can't begrudge them their feelings. The have every right to be angry and to act on that anger.

What does bother me, however, is the attitude of resentment towards the response to bird flu. The injustice here is the weak response to AIDS, not the strong response to bird flu.

[Clarification: I'm pretty sure the author of the original article doesn't really want bird flu to receive an ineffective response. I didn't mean to imply otherwise.]

I'll start with the hyperbole in the comment and just point out that the big panic today is not about the birds, of course, but about the people that will get sick and die if the disease spreads to humans.

The flu we hear about every year hits most people as sniffles, coughing, fever, and soreness. But for a portion of the population—newborn babies and the elderly—influenza is a deadly disease that kills about 35,000 Americans every year. Worldwide, the annual death toll is around a quarter million. It's the equivalent of the Indian Ocean tsunami of 2004 happening every year.

There are several active flu strains evolving from year to year, so every year we get hit by something a little different. In some years, the death toll rises to half a million. In a few years, it rises much higher.

If you asked any influenza epidemiologist about his worst-case scenario, he'd probably say it's a repeat of the Spanish Flu pandemic of 1918. Nobody is sure how many people died, but the lowest number I've found is 25 million, and nobody would be surprised if it really killed twice that many.

This brings us to the reason everyone is so upset about bird flu. It's genetically very similar to the Spanish flu. And based on the 100 or so human cases so far, the resemblance doesn't end with DNA. Bird flu has killed 40% of the people who've caught it.

[Update: According to Bird Flu Breaking News there have been 229 cases of bird flu in humans, 130 of them fatal. That's a 57% mortality rate.]

In a typical flu season, about 10% of the people in the United States come down with the flu. If the bird flu spreads to humans and follows the same infection pattern, it could kill 12 million people in this country alone.

Of course, that figure is a statistical fiction. Bird flu in humans is a rarity, so we are unlikely to have much natural immunity. The infection rate could be much higher than 10%. Then again, bird flu is presumably rare in humans due to some biological barriers. If those barriers hold, the infection rate in humans could remain tiny until the disease burns out in the avian population. Nobody knows how these factors will balance out.

Even if bird flu hits us hard, we really can't extrapolate what will happen based on our annual experiences with flu because we can do things to fight bird flu that we would never do to fight seasonal flu. We can cancel sporting events and musical performances and movies. We can close the schools for a few months. We can shut down non-essential businesses and restrict travel. We've seen influenza before, and we have some pretty good ideas what to do about it.

And that's the biggest reason you can't compare bird flu to AIDS: We know all about bird flu, but AIDS was something new and mysterious.

We didn't know what virus caused it, or even if it was a virus. It wasn't even clear that it was an infectious agent. Some doctors thought it might be a side effect of some new kind of club drug. That sounds strange now, knowing what we know, but at the time everyone knew of drugs that could compromise the immune system, but no one had ever heard of a virus with that ability.

And the kind of virus it was, a retrovirus, had only been identified as a class a few years earlier. The first AIDS cases presented with mysterious diseases. It took a while to figure out that these were opportunistic diseases, and that the main problem was with the patients' immune systems. Equipment for doing T-cell counts had only just started to become available.

It's been 25 years since AIDS was discovered. Descriptions of influenza have been found that date back 2500 years. It's an old enemy that we have learned how to fight.

I imagine that someday, eventually, AIDS will be an old enemy too. There will be ever-improving treatments for those infected, and a vaccine to protect those who aren't. AIDS will become just another once-deadly disease being held in check by medical science.

And maybe someday epidemiologists in Africa will spot a dangerous new strain of HIV emerging among the simian population and crossing over to humans. And maybe this strain will be just different enough from the known strains that our vaccines and treatments might not work as well as we're used to. That's pretty much what's going on with bird flu right now. Let's hope that any such new strain of HIV is handled like bird flu and not like AIDS was handled the first time it emerged.