Wednesday, Nov. 25, 2009

H1N1

We'll never know exactly when and where it began — and we still don't know how it will end. The disease was born in a pig, the result of a series of mutations, and from there jumped to human beings in southern Mexico, where it began sickening people in the winter and spring of 2009. By late April, cases had begun popping up in the U.S. Scientists were quick to identify the new pathogen — a never-before-seen H1N1 flu virus. By the end of April, cases were occurring in North America, Europe and Asia. For the first time in more than 40 years, the world was in the midst of an influenza pandemic.

Since the first scary headlines appeared, we've had good news and bad. Within a few months of the first cases, a new vaccine had been developed and tested and was being manufactured. Thanks to earlier worries about the threat of avian flu, the U.S. and other countries had pandemic-defense plans in place, along with stockpiles of antiviral drugs. But the response has been far from perfect, and some of the stumbles have made health experts quietly nervous about what might happen if a truly virulent pandemic strikes.

Manufacturing and distributing the vaccine were the first big problems. The Centers for Disease Control and Prevention initially promised that 120 million doses would be available by the end of October, but the true number was closer to 30 million, mostly because the antigen — the part of the vaccine that triggers an immune response — has been slow to grow.

With the vaccine in short supply, a smart method of distribution was vital, but around the U.S., there were long lines and confusion over who was responsible for getting the vaccine to the people who needed it. And bubbling in the background, partly because of voices from the far right and left, was a reluctance by many people to get vaccinated at all, born of fears — unfounded — that the vaccine was more dangerous than the disease.

More challenging than such political and logistic obstacles was the nature of the virus. With normal, seasonal influenza, it is the very young and very old who are most at risk. But from the first Mexican cases, doctors noticed that children and young adults were unusually vulnerable to H1N1, while the elderly showed some resistance. That set off alarm bells: a similar age distribution was seen in the 1918 flu pandemic, which killed at least 50 million people worldwide.

Fortunately, H1N1 hasn't been anywhere near the serial killer that the 1918 flu was. By mid-October, about 1,000 people in the U.S. were believed to have died from the illness — 100 of them children. That comparatively low toll is a very good thing, especially since H1N1 has ways of getting around that its 1918 granddaddy didn't. Airplanes are hothouses for viruses, picking them up in one country, circulating them for hours in a closed environment and then releasing them on the other side of the world.

Partly for this reason, the virus became widespread in nearly every state of the U.S. by fall, prompting President Obama to declare a national emergency. In southern-hemisphere countries like Argentina and New Zealand, where the winter flu season runs from June through August, waves of the sick nearly overwhelmed hospitals. In the event that things got severe up north — say, a quarter of the population falling ill — U.S. hospitals would lack the surge capacity to deal with the sudden influx. "If we increase by 30% the number of cases at any one moment over what we saw in June and July, we are going to overrun intensive-care units," says Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.

That ominous fact makes vaccines all the more vital, and the Federal Government deserves credit for its crash program. Normal seasonal-flu vaccines take about nine months to develop and manufacture, but the H1N1 vaccine was ready to go in less than six months. Speeding things up much more would not be easy. Vaccine production is a laborious process that depends on chicken eggs as a growth medium. "We are not cutting corners," says Anne Schuchat, director of the National Center for Immunization and Respiratory Diseases.

Still, the government finds itself in a no-win situation — criticized for the slow distribution of the vaccine, even as many Americans worry that it hasn't been fully tested. In the meantime, we've had to learn to live with the pandemic, which has changed our lives in ways large and small. Beer pong is being banned on college campuses to slow transmission; Catholic parishes have restricted wine at Communion for the same reason. So far we've been lucky, but there's no guarantee that luck will hold.