There's news out this week that feels almost impossible to deliver without an eyeroll: The CIA has promised that it will "never again" use an international vaccination campaign as a cover for intelligence gathering.

I can't see why not. I mean, the last attempt ended so well.

(Yes, that was sarcasm.)

A fuller version of the news: The White House, speaking for the CIA, has responded to a letter sent by the deans of 12 graduate schools of public health across the United States. In that letter, sent in January 2013, the deans stated forcefully: "Public health programs should not be used as a cover for covert operations."

To understand the importance of the letter, it's necessary to track back through a bit of history dating back three years. Briefly: An international campaign to eradicate polio, begun in 1988 and costing billions of dollars, has been derailed and rendered an international emergency, with dozens of murders by Islamist extremists, because the CIA decided to use a fake vaccination campaign as a cover for attempting to identify now-deceased terrorist Osama bin Laden by stealing his family's DNA.

No, that was not from the Onion.

The short version of this story – which preserves the WTF shock of the original, I hope – is that in an attempt to find bin Laden, the CIA set up a hepatitis vaccination campaign in Pakistan, the actual goal of which was to extract DNA from bin Laden's children in an attempt to match it with DNA from bin Laden's sister, to see if they could narrow down the locations where bin Laden might be hiding out. The covert op did not find bin Laden (he later was identified by other means), and the hepatitis vaccines were useless, because only one dose out of several was given. The Pakistani doctor was identified by his own countrymen and prosecuted, and the most visible Western-linked immunization campaign in Pakistan, against polio, understandably became a target of suspicion. Pakistan was already one of the world's hot spots for polio – one of just three, down from 125 countries when the international campaign began. Thanks to the suspicion brought by the ruse, extremists murdered a number of polio immunization teams, other vaccinators became afraid for their lives, the disease rebounded, Pakistan became an exporter of polio, the country was put under very unusual "vaccination on exit" orders by the World Health Organization, and polio, almost beaten, became an international emergency again.

Because the entire story is so jaw-dropping, it's worth reading the granular details. Here's a curation of my own stories on this, in chronological order so you can see where it all started and where we are now.

July 2011: File under WTF: Did the CIA fake a vaccination campaign?

July 2011: Is polio eradication slipping out of reach?

August 2011: How a US court case explains problems eradicating polio

August 2011: Borders are irrelevant: Polio returns to China

October 2011: Scathing report: Polio eradication "not... any time soon"

May 2012: Update: Pakistan, polio, fake vaccines and the CIA

December 2012: Taliban murders six immunizers in the wake of CIA polio ruse

January 2013: Polio eradication: The bad news continues

May 2014: Polio declared an international health emergency

If you look at those, you'll perhaps understand why the announcement that the CIA promises to not-distort future international vaccination programs has been met with derision. Other campaigns to eradicate other crippling, killer childhood diseases – measles, notably – were going to be launched by international health authorities after polio was beaten. Instead, in good part because of the CIA's actions, polio remains not beaten, and no one knows when it will be. The other campaigns, against other diseases, will have to wait. No one knows how long.