The first influenza pandemic of this century has spread to virtually every country in the world with a speed reminiscent of its close relative, the catastrophic 1918 flu pandemic, also caused by an H1N1 strain. As captured in images of lifeless young bodies being carted away in wheelbarrows on the streets of New York, that pandemic claimed over half a million American lives and more than 50 million worldwide, indelibly imprinting the medical psyche with fear that any year might bring a disastrous pandemic—even though pandemics strike on average once every three decades. In the years since, envisioning the worst has led to extraordinary levels of highly beneficial national preparation and international cooperation—and too much doomsday rhetoric. So far, however contagious and miserable its symptoms may be, this pandemic, now resurging as expected this fall, is among the mildest, rated a category 1, similar in ferocity to ordinary seasonal flu. The 1918 pandemic would have clocked in as a 5, the worst category.
Yes, today's outbreak could change quickly. But it's time to give up the ghosts of 1918 that so haunt our medical thinking. Our challenges today are not what they were when we had nothing to offer but are more about knowing just what to offer, when, and to whom. This pandemic promises to teach numerous lessons that will inform future crises. Some are already evident:
1. Confirm cases; don't guesstimate. Commercial technology can rapidly and precisely identify the strain of flu involved, but it is not routinely used unless the patient is very sick. Most influenza-like illnesses get treated based on clinical symptoms alone, and in the midst of a pandemic, the tendency to overuse antivirals and antibiotics is real. Overtreating increases the threat of resistance to antiviral drugs like Tamiflu and Relenza at a time when there are no good alternatives. And when vaccine scarcity is a concern, patients with a confirmed diagnosis don't need a dose, sparing it for others who do. Some doctors have also complained that other illnesses are being missed because, without confirmation, symptoms are assumed to be swine flu.
2. Figure out what makes people susceptible. Younger people are hit hardest by pandemics; the elderly, by regular flu. We really don't know why, though it's suspected that elders have somehow acquired immunity over the years and that some younger people overreact to the novel microbe; their youthful, vigorous immune systems heighten the inflammation in the airways and lungs caused by the viral infection. Pregnant women are another mystery at-risk group, though a surprising study out this month shows that to be true mainly of a small subset who have depressed levels of an antibody, IgG2, that is known to fight off viruses. If it's proven that this immune marker or others can identify susceptible groups, priority vaccination or antiviral drug use could be more targeted, sparing resources in a time of high demand.
3. Intense treatment of severe pneumonia is cost effective. Influenza kills by causing an overwhelming pneumonia. Unlike back in 1918—before antiviral drugs, antibiotics, steroids, intensive care units, arterial oxygen measurement, and mechanical ventilators—we can now cure most pneumonia. And treatment of the sickest is improving. British investigators have recently reported good results in patients near death with pandemic flu using extracorporeal membrane oxygenation, a technology that pumps blood through an oxygenator like the one used in heart bypass surgery or in neonatal intensive care units for infants unable breathe. ECMO rests the lungs and gives them time to heal. These researchers have shown that ECMO for acute respiratory failure in adults not only improves survival but is also cost effective compared with conventional treatment using positive-pressure ventilator support.
4. Vaccine technology must improve. What's lost in the talk about this fall's two separate flu vaccines is that neither is likely to have much impact. The seasonal flu vaccine we have in hand doesn't work for swine flu, which accounts for about 90 percent of what's circulating, and the vaccine that will protect against H1N1 won't be distributed in time to make a difference.