The Smallpox Eradication Campaign
"While doctors sign the death certificates of people, today we are signing the death certificate of a disease."
-- Dr. A-R. A. Al-Awadi, President of the 33rd World Health Assembly
When I was a kid, I asked my mom about the strange circular white scar on her arm, and she told me that it was the scar from her childhood smallpox vaccine.
Later, as I read occasional mentions of smallpox in history books, smallpox seemed like a distant thing that'd vanished back in the mists of time. But my mom's vaccination scar reminded me that smallpox had only been driven to death recently. So, when I was sick with COVID earlier this year, I decided to read the official WHO writeup of the smallpox eradication campaign, and then continue with books by two of the scientists leading the campaign: Dr. Henderson(the director of the eradication program), and Dr. Foege(who led the Indian part of the program).
It was a noble campaign, deserving of much poetic praise. But despite the amazing effort, I'm now realizing it doesn't deserve the aura of great accomplishment it's been heralded with. "Never forget what we are capable of" is not the full lesson; rather, the campaign should also call us to humility and an urge to do better next time.
And, the recent news should tell us the next time might be soon - and that the smallpox campaign left some unfinished business.
History of Smallpox
"Because smallpox is now extinct, we have to take the unusual step, in the clinical description of a human disease, of referring to it in the past tense."
-- Smallpox and Its Eradication, by the WHO Global Commission for the Certification of Smallpox Eradication
Smallpox dates back at least to the New Kingdom of Egypt, where it killed both Pharaoh Ramesses V and the workers who mummified his body. However, it died off from the Mediterranean for centuries till it probably came back as the Antonine Plague (to historians' best guess at identifying it) - killing maybe as much as a third of the empire's population, 25 million people - and stayed into the modern era.
Up until eradication, there were no treatments for smallpox once you fell sick. (There's one recently-developed antiviral that's thought to help, Tecovirimat, but of course it hasn't been tested.) Death rates varied between 10-30% in standard smallpox (called Variola major), and 1-10% in a less-severe mutated form that emerged in the 1800's (Variola minor).
The first prevention to be found was variolation, once called inoculation. Once someone survived smallpox, they were immune for the rest of their life. So, in variolation, healthy people were intentionally given a small amount of smallpox virus (usually in a scratch in their arms), in hopes they'd have a mild case and then be immune. Variolation was discovered in eastern Asia (probably in eleventh-century China), practiced in the Middle East by the 1200's, and then brought to Europe in the 1700's. Variolation had significant death rates - about 2% in 1721 Boston - but that was far better than the 10-30% death rates from standard smallpox.
“In 1736 I lost one of my sons, a fine boy of four years old, by the smallpox taken in the common way. I long regretted bitterly and still regret that I had not given it to him by inoculation. This I mention for the sake of the parents who omit that operation, on the supposition that they should never forgive themselves if a child died under it; my example showing that the regret may be the same either way, and that, therefore, the safer should be chosen.”
-- Benjamin Franklin
Then, in the 1790's, Edward Jenner heard milkmaids saying that catching cowpox from cows protected them against smallpox, without the risks of variolation. He tested it - and it worked. Giving people cowpox (a small amount of cowpox virus in their skin) meant they were immune from smallpox, just as if they'd had smallpox. By modern standards, this first vaccine was (and still is) very bad: it's a live virus, so it gives you a fever for about a day and a faint permanent scar, and occasionally it has much worse consequences (up to, rarely, death). The traditional vaccine still does that to people who get it today: it literally is live vaccinia virus. But it was a breath of life to people facing epidemic smallpox.
The vaccinia virus we have now has been passed through humans and cows and horses ever since Jenner's day, with one lab cow infecting another every few months to produce another batch of vaccine. (Nowadays, labs use cell cultures instead of cows, to avoid contamination; and there's a newer vaccine which kills the virus after harvesting it from the cultures.) Jenner got it from the disease of cows he called "cowpox," which he claimed to be derived from the disease of horses he called "grease." But, the cowpox virus we see today is only distantly related to vaccinia:
Perhaps vaccinia virus was derived from some other orthopox virus by mutations from successive passage through lab animals and people. (The WHO book suggests cowpox; camelpox seems more likely to modern epidemiologists.) Or, perhaps vaccinia virus no longer exists in the wild. Perhaps chance gave Jenner the right moment to grab a natural vaccine that was about to go extinct - or, at least, extinct within Europe.
The Idea of Eradication
"Future nations will know by history only that the loathsome smallpox has existed."
— Thomas Jefferson, letter to Edward Jenner, 1806
Finally, thanks to vaccination and re-vaccination and public health quarantines, smallpox got eradicated from Europe, the Soviet Union, and the United States. But that didn't eliminate the problem even in those countries. Though they required everyone entering the country to be vaccinated, unknowingly-sick travelers still kept bringing in smallpox.
For example, the last smallpox outbreak in the United States, in 1947 New York, was started by one sick merchant returning from Mexico. Twelve cases and two deaths followed - held down to only twelve cases by over six million vaccinations. Berton Roueché, writer of epic medical dramas, describes this outbreak in his "The Man from Mexico." Unfortunately, what he doesn't mention is the >46 cases of serious reactions to the vaccine, including at least three deaths. More New Yorkers had died from the vaccine than from smallpox. Still, that's what it took to contain smallpox. Mass vaccination of schoolchildren - like my mom - continued for more than a decade afterward.
This proof that eradication was possible, and this continued risk and cost of mass vaccination, motivated people to publicly suggest with growing seriousness that smallpox be eradicated globally. Finally in 1959, when the Soviet Union (tired of repeatedly stamping out imported smallpox in Soviet Central Asia) officially proposed global eradication to the World Health Organization, the WHO endorsed the plan.
For the next several years, the endorsement was just words on paper. That was expected - at the time, the World Health Organization was nothing more than a consulting group for national programs. Unfortunately, smallpox eradication would take a lot more than that. Even though scientists had recently learned how to freeze-dry the smallpox vaccine so it wouldn't go bad in tropical weather, most third-world countries had next to no public health system to do mass vaccinations. And, many of the countries which did have primitive public health systems were sensibly concerned about threats more acute than smallpox, like tuberculosis and malaria. (The countries with Variola minor smallpox, which killed "only" ~1% of patients, were especially reluctant to give it their limited attention.)
What's more, the WHO and foreign aid workers themselves were reluctant to get started. Unfortunately, just before smallpox eradication was proposed, yellow fever and malaria eradication campaigns had abjectly failed. Both those diseases had animal reservoirs: animals regularly carried the disease and infected humans. So, even when the yellow fever campaign had identified and isolated every sick person in a region, people would catch it anyway from animals - and workers couldn't even identify all the sick animals, let alone isolate them or vaccinate their contacts. Nobody had realized yellow fever had this animal reservoir till partly through the campaign - so for all they knew, smallpox might too. (It turned out that it didn't, despite a brief scare before monkeypox was identified as a distinct illness. But nobody knew that at the time.)
The original Soviet resolution had proposed smallpox could be eradicated with five years' effort. Six years later - in 1965 - nothing had been done.
Finally, in 1965, the US Association for International Development, searching for a public health program that would have lasting effects in western Africa, decided to run a smallpox eradication campaign. This spurred the WHO to intensify its own campaign and actually vote meaningful funding the next year. But even then, the Campaign's new director had a shoestring budget (though a significant fraction of the WHO's then-tiny budget) and bureaucratic challenges even to the point that the WHO prohibited him from publishing his own newsletter.
Every country in the Intensive Eradication Program has its own story, and all of them are told in a wealth of detail in Smallpox and Its Eradication. I won't repeat them all for time's sake, but I'll talk about some to show common threads and illustrate the points I want to draw out. The program wasn't very coordinated, but it succeeded in spite of this because eradicating smallpox wasn't as hard as they'd thought.
Contact Tracing
The first advantage was that they really didn't have to vaccinate everyone.
One day in 1966, Dr. William Foege - an epidemiologist and former missionary now hired by USAID for the eradication program in Nigeria - found a smallpox patient in his village. He knew this meant there was about to be a regional outbreak. The traditional, simple approach would've been to vaccinate everyone in the region. Unfortunately, he only had a small amount of vaccine, and the looming civil war had cut the supply lines so he couldn't get more.
What he did was figure out where the vaccine would do the most good. He vaccinated the people in his small village, since there was already an infectious patient in the village, and since everyone there might have been exposed. Then, he figured out who else was at risk: he radioed missionaries in other nearby villages to find who currently had smallpox cases, and then vaccinated them with the remaining vaccine, as well as a few nearby villages where infected people would most likely have traveled.
The outbreak immediately ended. Foege didn't need any more vaccine. There was no one still unvaccinated in a place where they could get smallpox.
Still, for the moment, Foege returned to mass vaccination as soon as he moved to another city with better supply lines. But, even after he'd vaccinated 94% of its population, smallpox nonetheless broke out there - around one church who'd refused vaccination for religious reasons. As soon as someone had gotten sick there, they were near a lot of vulnerable people to spread it to.
This convinced Foege that mass vaccination was completely the wrong way to look at things. As long as there were any clusters of unvaccinated people left around smallpox patients, population-wide vaccination numbers didn't matter because the disease could still find vulnerable people. To interrupt transmission and eradicate smallpox, you needed to focus your vaccination on getting all the patients' likely contacts. Contact tracing was already practiced with rare diseases in First World countries, but this was the first time it was applied in the Third World in the middle of epidemics.
By 1968, this was official US CDC policy - and with it, smallpox was permanently eradicated from West Africa in 1970. Shortly thereafter - as Dr. D. A. Henderson from the CDC became director of the WHO eradication campaign - it became WHO policy as well. From then on, the WHO told workers to go out and identify every case of smallpox (rather than trusting traditional reporting systems), and then vaccinate all likely contacts. Contact-tracing and targeted vaccination was better than mass vaccination.
How Smallpox Was Easy To Trace And Eradicate
Fortunately, it was only realized during the campaign, smallpox was an unusually easy disease to contact-trace and vaccinate against.
The biggest advantage was that people could get a vaccine even after being exposed to smallpox. Because a vaccine gave you a large dose of vaccinia virus at once, it produced a faster immune response than smallpox. So if you vaccinated someone at the same time as they were exposed to smallpox, or even a day or two later, they'd still be protected. This was very useful during the campaign. When workers traced someone down as a recent contact of a smallpox patient, they didn't need to isolate them; they just needed to vaccinate them. They didn't even need to fully isolate patients: standard practice was to put them in a guarded hut and let anyone visit, but just insist on vaccinating the visitors first. This made it actually practicable to watch patients, who'd often fight being isolated.
And what's more, workers knew who to contact-trace from. Smallpox was only contagious once people had started showing symptoms - and the first symptom, almost always, was a very distinctive rash which even young kids could identify. In fact, there was one lazy field worker in Indonesia who didn't go search for patients, but just showed schoolchildren pictures of smallpox patients and asked if they'd seen anyone with those scars... and the kids named more patients than other workers found personally. (Identifying more patients, of course, meant better contact tracing and better prevention of new infections.) After that, the WHO produced standard pictures of smallpox patients to put on billboards and hand out to kids.
It was possible to get an asymptomatic case of smallpox, but in the field no one tested for them. The WHO writeup mentions one study where asymptomatic contacts were tested and found to have smallpox virus in their blood - but they treated that as just a lab curiosity. In the field, no one tested for it, and just about all cases were tracked down to contacts of known symptomatic cases. So, asymptomatic people must not have been contagious. (There was one case in Sweden, but the campaign's succeeding means that must have been a unique exception.)
(This lines up, incidentally, with somestudiesabout measles virus where vaccinated people exposed to a measles patient didn't get symptoms but nonetheless had the virus in their blood. We haven't seen epidemics of measles break out with no known cause, so measles "asymptomatic cases" must also not be contagious. It thus makes sense that would be the case for many other viruses as well.)
Another big advantage, frankly, was that privacy concerns didn't seem to be an issue. Once the national government and local tribal leaders supported the campaign, they could bring down the full force of law (or the practical "law" of tribes) to find, identify, and guard infected people. Without this, the campaign would've probably failed. For example, in Pakistan, so many eradication workers stopped so many migrant tribes that they started giving out certificates of inspection, so that another worker wouldn't stop them and check everyone over again a couple days later. If it wasn't for this, cases would've been missed and probably spread to more isolated communities. In India, the program had to regularly search house-to-house and post guards outside the houses of smallpox patients, as well as sometimes shutting down long-distance travel for unvaccinated people. Also, after smallpox had been otherwise eradicated in southern Africa, it kept spreading among a Botswana anti-vaccination religious sect until they finally gave in to vaccination when the government threatened to expel them from the country. If it wasn't for this - if privacy concerns had stopped the surveillance program - it probably would've been stymied many times. At the least, it would've taken much more effort - and Foege opines that much more effort being required would've sunk the program.
Finally, smallpox vaccination worked even better than previously assumed. The standard recommendation was (and still is) to be revaccinated every five years. But a lot of the time, even one single childhood vaccination protected someone from smallpox for life - it wasn't total, but it still gave substantial immunity.
But still, sometimes a vaccination just didn't take. Fortunately, with a live-virus vaccine, it was possible to check. If your vaccine "took," you'd get avaccinia-virus infection which would cause a visible pustule for the next couple weeks before fading away to the faint lifelong scar I saw on my mom. The campaign would regularly check on its vaccinators' work by checking that >90% of people they supposedly vaccinated had that pustule. Of course, it was still possible - though very unlikely - for someone to catch smallpox even shortly after an apparently-successful vaccination. Such rare vaccine failures were a fact of life.
(So, we shouldn't be surprised by vaccine failures. When people were mass-vaccinating in places with active smallpox, we saw the smallpox vaccine sometimes fail too. Until COVID, America just hasn't recently had any mass outbreaks of diseases where there're vaccines - except for the flu, but the vaccine isn't so good there.)
How The Real World Was Still Difficult To Surveil
On top of that, even when there was government support, it sometimes didn't translate into support on the ground. This was starkest in Afghanistan. Until I'd read about this campaign, I hadn't appreciated how ungoverned Afghanistan was. Even in the 1970's (before the Soviet invasion), the government's writ scarcely ran outside a few major cities. The eradication campaign needed to convince each tribal leader, and then track down cases despite a near-total lack of roads. Director Henderson privately thought this would make Afghanistan the last holdout of smallpox (as it and Pakistan today, in fact, are the last holdouts of polio).
But - to Henderson's surprise - the tribal leaders were convinced. Smallpox was a problem they recognized, and once the vaccinators explained things to them, they were happy to work with them. The vaccinators were even allowed to vaccinate women isolated from men inpurdah. (The wild plan to recruit female Peace Corps volunteers from the US specifically for that purpose proved to be unnecessary.)
It was much the same situation in Ethiopia, with a civil war on top of tribal autonomy. At one point, a vaccination helicopter was captured by rebels - and released unharmed for only a small ransom, after the rebels had themselves gotten vaccinated. But then, the situation became more unique when Somalia invaded. Fortunately, Somalia was willing (with only a little prodding) to let the eradication campaign continue - which it did, through the intermediary of local Ethiopian volunteers since the WHO was unable to officially work with the Somalian government involving what was still officially Ethiopian territory.
This same official policy had earlier been significant in Sudan, where at one point a rebel delegation showed up to the WHO field office asking for the vaccine for people in territory they held. They were happy to give it to them, though due to official policies they had to mark the vaccines down as "lost."
(Tragically, now, the polio eradication campaign can't repeat that success. On top of the war in Afghanistan (where the Taliban was a lot better at allying with those tribal leaders), the CIA used fake polio vaccination workers to find Bin Laden. So, quite sensibly, Afghanis and Pakistanis today won't trust vaccination workers. Maybe someone else like China or Iran could actually eradicate polio there... but maybe not.)
Variolation
"[Smallpox vaccine] also does not endanger others by contagion, in which way the small-pox has done infinite mischief..."
— Letter to Edward Jenner, 1798
The biggest challenge in Afghanistan and Pakistan, ironically, was variolation. As I mentioned above, variolation meant giving people actual live smallpox virus. So, in addition to potentially killing the patient, it could spread smallpox to vulnerable people nearby. Variolaters in the West had usually isolated people while they were sick, but that wasn't always the case (especially in Asia). Also, they tried to give their clients a mild case of smallpox by giving them a small amount of smallpox virus - but that could still spread a severe case to someone else if they weren't isolated.
Fortunately, the eradication campaign convinced most variolators in Afghanistan and Pakistan to become vaccinators instead. And amid that vaccination campaign, the few variolators who weren't convinced were driven out by lack of smallpox scabs to source virus from, and lack of demand. The last smallpox case in Afghanistan had a variolator take samples of his scabs - but nothing further happened. Without any more smallpox, and with access to vaccines, no one was interested in variolation before the variolators' virus samples expired.
(Meanwhile in China, some variolators in Inner Mongolia kept their smallpox virus supply fresh by variolating their own children one by one, year after year. Eventually this spread and actually caused an outbreak after smallpox was otherwise eradicated in China. Fortunately, it was discovered and stamped out while the outbreak was still limited.)
These variolators provided a natural experiment on how long the smallpox virus would survive, so as to be sure it wouldn't come back after eradication. There'd been stories of people catching it from dead victims' houses after many years, but it'd never been proven to be due to the house. Every variolator contacted said that their virus samples couldn't be depended on to be infectious for more than a year. Twenty samples from Pakistani and Afghan variolators were tested in the laboratory, and this was borne out. So, if eradication could be held for a year, variolators - and houses - wouldn't be a problem.
India
India, everyone knew, would be the biggest challenge for the campaign. It was thought to be the original home of smallpox. Even by its inadequate reporting (which was probably reporting <10% of cases, perhaps <1%), it contained ~60% of the world's smallpox cases. The Ganges River Plain was so densely-populated that even if 80% of every community was vaccinated, the population of unvaccinated people left over would be as large, and as dense, as if no one in the United States was vaccinated.
Dr. Foege (whom we last saw in Nigeria) was assigned as the chief WHO liason to India. They needed all his skill - epidemiological, administrative, and persuasive.
One of the first tasks was to send workers out to each district in each state in India to search for smallpox cases. Even this simple task, in a country as populous as India, required large armies of temporary staff. Horrifically, the first incomplete search (in Uttar Pradesh and Bihar states), during the light season for smallpox, revealed over 9,000 previously-unreported cases, in 90% of all districts. The team simply didn't have enough staff to even pretend to contain this, so they decided to just vaccinate the closest contacts for as many cases as they could... and then do another search the next month, and repeat in other states. Even more horrifically, that second search revealed many more cases unlinked to any case that'd been reported the previous month, meaning those >9,000 cases hadn't been anywhere near complete.
Even after the searches started nearing completeness, they needed constant infusions of money and trained epidemiologists to contain the patients - and then even more, after his team discovered patients slipping out of their quarantine huts while the posted guard was momentarily gone. On top of that, there were a number of other small concerns, like having to feed and compensate professional beggars in quarantine. For months, it felt like the eradication program was making no progress, while case counts grew and grew.
But the team did hang on, through years of grueling work, despite Director Henderson's skepticism of their ability to keep up. Many of them had health problems - Foege himself had a herpes infection, another had pneumonia, but they kept on working. They wrote procedure after procedure, form after form, for an army of searchers and vaccinators and guards and messengers - "India's vast bureaucracy" (as Foege called it) coming to their aid. "We've considered the question," Foege said, "and have decided that things can't get worse; therefore they must get better."
Things did - seemingly - get worse. Finally, the Indian government insisted that the quarantine and ring-vaccination program wasn't working; they needed to fall back on mass vaccination. Foege knew that would fail; he pleaded with the minister in private and then in a public meeting. Finally - in the public meeting, with the minister still unconvinced - one junior vaccinator commented that when a hut was on fire, no one wastes time dumping water on far-away houses; they dump it where it will do the most good.
Surprisingly, that convinced the minister: on the spot, he said he'd give them one more month.
And then, the search later that month showed they'd turned the corner. A couple months later, the case count went down. There were more crises, but finally - after a few more exhausting years of work, but only a few years - smallpox was eradicated in India and the surrounding nations.
Monkeypox
But it could be argued the eradication campaign left some unfinished work.
At one point in 1970 - after smallpox had been eradicated from west and central Africa - someone from a remote village in Zaire showed up with obvious symptoms of smallpox. A sample was quickly flown to the US CDC for analysis, and investigators went to work trying to find out how in the world he could've been infected. At the back of everyone's mind was the fear that he could've been infected from an animal. If animals could carry smallpox and infect humans - if there was an animal reservoir for smallpox - then it would probably never be eradicated. That was what had recently sunk the yellow fever eradication campaign.
Fortunately, the lab analysis showed he didn't have smallpox. Unfortunately, he had a new closely-related virus, which was named monkeypox. Research showed that monkeypox was clinically indistinguishable from smallpox, and the smallpox vaccine is also largely effective against monkeypox because both viruses are related. (Remember the vaccine is another related virus, Vaccinea.) Monkeypox didn't spread well between humans, but several cases per year kept occurring in remote villages, presumably caught from animals. A WHO workgroup was formed to continue studying monkeypox, but people largely didn't worry about it.
What they didn't fully appreciate at the time was that even in those remote Zaire villages, most people had been vaccinated against smallpox, and that was why it didn't spread so well between humans:
After smallpox was eradicated, smallpox vaccination (understandably) stopped. This meant people were much less resistant to monkeypox too... and (unsurprisingly in retrospect, though I haven't read about anyone anticipating it at the time), monkeypox cases rose significantly, even before the current outbreak.
It's very possible, however, there're other factors behind the current outbreak. Death rates are much lower than previous monkeypox outbreaks, and most cases have only a few pock marks around the site of infection (in the genital area). This sounds very much analogous toVariola minor. That mutated variant of smallpox also had much lower death rates and only a few pock marks often around the site of infection.
Paradoxically, it's very possible that the current monkeypox variant might be less infectious than previous variants (just like Variola minor was less infectious than Variola major). Genetic analysis shows that the current outbreak traces back to the 2017 Nigerian outbreak. Then as now, it appears to be primarily a sexually transmitted disease. Even close nonsexual contacts rarely get it. Any disease that can be transmitted at all can be sexually transmitted; we call a disease "sexually-transmitted" when it's so bad at transmission that essentially no other method works. So, what led to this current outbreak is likely a less-contagious "Monkeypox Minor" - a variant of monkeypox analogous toVariola minor- which happened to spread into first the prostitution network in Africa and then the sex party network of the West.
Fortunately, monkeypox is less severe than smallpox - and this "Monkeypox Minor" is less severe still. But monkeypox does have an animal reservoir, so it can't be eradicated with current methods. We can vaccinate and isolate sick people, but animals keep carrying it and reinfecting people. There's nothing we can do about that.
What we should try to do is keep it from getting into wild animals in the West. Bubonic plague can be carried by animals, but animals outside Eurasia didn't get it until the Third Plague Pandemic around 1900. Now, people around the world occasionally catch it from wild animals. The current pandemic probably being less infectious will hopefully keep monkeypox out of wild animals outside Africa... but the government should take more steps than it currently is to make sure it doesn't get permanently established in animal reservoirs around the world.
The Future
So in short, the smallpox eradication campaign suffered from inadequate support, a shoestring budget, and lots of local non-cooperation. Despite the blithe summary in history books, humanity did not simply come together to defeat the disease.
Fortunately, even the partial efforts we could muster were enough. The vaccine was better than expected, the virus was slightly more vulnerable than expected, and it turned out we didn't need to vaccinate anywhere near everyone as long as we vaccinated the right people. We aren't mastering disease, but smallpox was uniquely easy.
We should rejoice over the eradication of smallpox, but it should also be a warning. If this is one of our few triumphs of its type, how could we face more serious challenges? Indeed, thirteen years ago, Director Henderson was fully convinced that we shouldn't even bother trying to eradicate any other disease, because every other disease would be much harder to eradicate than smallpox. Since then, we've almost eradicated guinea worm and polio... but they took much longer than smallpox, and haven't quite been finished (as the recent presence of polio in New York State reminds us.)
COVID, for example - despite people's determination to eradicate it - is more difficult to eradicate than smallpox in just about every way. To start with, it's contagious before you have symptoms, and the symptoms are much less distinctive. There's no way to tell by looking at someone whether they have COVID. On top of that, the vaccines aren't as good, and many people don't trust or want them (unlike how just about everyone trusted and wanted the smallpox vaccine). Most other diseases fail at least one of these criteria. And - to render all these questions moot - COVID has animal reservoirs. Even if somehow magically every person on earth cooperated and isolated for two weeks and got tested and vaccinated, the disease would come back from animals.
The lesson that governments and public health programs did take from the smallpox vaccination campaign was to expand more public health efforts through the Third World. Now, the WHO is much more active, and foreign aid to Third World health programs is much more common. That was a very good lesson. It's not as shiny and quotable as the once-for-all eradication of smallpox, but it's probably the most practicable thing to do - and if we somehow do manage to eradicate another disease, it would be because of that sort of plodding work.
And, the current monkeypox outbreak has brought forth those shortcomings in a more weirdly rhyming way than Director Henderson knew. The smallpox eradication campaign worked in that it did in fact eradicate smallpox. But despite it, we have not mastered disease.