The elimination of smallpox is often hailed as one of the greatest triumphs of modern medicine and public health. It is a stunning achievement - with the concerted effort of the World Health Organization, a scourge of mankind was wiped off the face of the earth in a matter of one decade (well, almost eliminated). That success led to the belief that other diseases could likewise be eliminated, if enough effort, strategy and dedication was put to the task. The shortlist included yellow fever, polio, and measles.
Well, so much for good intentions. Turns out smallpox was uniquely suited to elimination - as a human-specific virus, it couldn't hide in another species, waiting for an opportunity to reappear. Alas, polio and TB and measles aren't quite so tidy. Last week, the WHO conceded that it's effort to eliminate polio may never work. Measles isn't gonna happen because it simply doesn't generate the passion (or fear) that smallpox once did. The simple fact is that disease is extremely agile, relentless, and tenacious. It is happy to wait us out. And it is expert at routing around our magic bullets.
It reminds me of the CDC's announcement in 1989 that designated 2010 as the target date for the eradication of tuberculosis from the US (not worldwide). Sure enough, within a couple years TB rates in the US were headed up, not down - seems drug-resistant strains, combined with HIV, gave TB a fighting chance.
It is, of course, disappointing to see the WHO scale back, or at least moderate its goals for polio. But perhaps realism is a better longterm weapon than idealism.
(image from The UC Atlas of Global Inequality)