And it comes at a time when a disease we were working on eliminating, measles, has come back and the US is about to lose its measles-free status.

It sounds as if his legacy is to be unique, a feat never to be accomplished again.

  ...The program was ultimately unsuccessful in locating Osama bin Laden. It led to the arrest of a participating physician, Shakil Afridi, and was widely ridiculed as undermining public health.[2][3] The program is credited with increasing vaccine hesitancy in Pakistan[4][5][6][7] and a rise in violence against healthcare workers for being perceived as spies.[8] The rise in vaccine hesitancy following the program led to the re-emergence of polio in Pakistan, with Pakistan having by far the largest number of polio cases in the world by 2014.[8]

Food produced by Fritz Haber's Haber-Bosch process (making fertilizer) supports about half of the world's population.

I think https://en.wikipedia.org/wiki/Louis_Pasteur wins this one, though.

Norman Borlaug probably comes close. H. Trendley Dean was also impactful on a large scale, while its seemingly less important it helps a lot of people.

Politicians and empire-builders (Elon) is currently standing in the way of human progress and history.

Is there any way that people can work to re-introduce it into society? I know some folks are making a lot of progress with MMR.

Genghis Khan??

Nobody in Hn type circles wants to remember it because looking back with hindsight it was clearly just part of the theater to get people wringing their hands about whatever chemical or biological WMDs they alleged Saddam had and they killed the program as so as they got their invasion.

Wikipedia somehow makes it eve worse than that:

"The campaign ended early in June 2003, with only 38,257 civilian health care workers vaccinated, after several hospitals refused to participate due to the risk of the live virus infecting vulnerable patients and skepticism about the risks of an attack, and after over 50 heart complications were reported by the CDC."

Smallpox is not measles! But, point taken.

And to see himself become the villain.

If you don’t keep it then the first time you’ll get to study it will be when the first bodies are recovered from your cities.

This is tangential to your point, but smallpox vaccine protects against mpox (the virus formerly known as monkeypox) and the CDC still recommends it for people in certain mpox risk groups.

Most people nowadays are not vaccinated against smallpox anymore

It really is eradicated - it's the only human disease we've truly eradicated. There are literally no more cases of smallpox in the wild, period.

The problem is that there are samples of viable virus in the labs of the US and Russia. So - it's eradicated but we have to keep stockpiles of vaccine around anyway. But nobody gets vaccined for it any more; it has an unfavorable risk-benefit ratio when the virus simply does not circulate. Smallpox kills ~30% of people who get infected with it; the first-generation vaccine had a mortality rate of about 1 in 1,000,000.

(There are newer-generation vaccines developed and being developed that have an even better safety profile but we still wouldn't use them because the cost - the literal cost and the side effects and general "meh, why get another shot?"-ness outweighs the benefit of protection against something you don't need protection against.)

We don't vaccinate against smallpox, but keep in mind that at least two countries maintain live smallpox virus in government labs.

The bad actors are predictable. And I suspect at least two others are lying.