February 18, 2014 8:24:33 AM
There is a lot that the human species has messed up, from violations of human rights to ruination of the environment. Here is something we can be justly proud of: we have eliminated smallpox. We don't even have to think about smallpox now, so we might not give ourselves the deserved credit for this accomplishment. Because we axed smallpox, we can have hope for ending also polio sometime soon, and maybe other diseases. That's the optimistic story within The End of Plagues: The Global Battle Against Infectious Disease (Palgrave Macmillan) by immunologist John Rhodes. Though Rhodes concentrates on smallpox, from the ways people tried to control it before there was a vaccine to its being declared eradicated in 1979, there are updates here on the battles against malaria, flu, polio, and others. It is a grand story of progress, with plenty of bumps along the way.
We have no smallpox now, so it is hard to imagine how fearful a disease it was, "the most terrible of all the ministers of death," one writer called it. Doctors might have thought they were accomplishing something with their purges, blistering, and bloodletting, but there was actually nothing that could be done in the way of a cure. A patient would be stricken with fever, aches, rash, bleeding, and toxins in the blood. The course of the disease was variable, with some patients having no residual effects, some getting the classic pox skin deformities, and some (around 30%) dying. It replaced the black plague as the most feared killer in Europe, and although people had no idea of viruses or immune systems in the eighteenth century, observers before Edward Jenner's discovery of vaccination knew there was something they could do about the disease beforehand. This was variolation, the practice of deliberately inserting material from one person's smallpox lesion into the skin of an uninfected person. This worked if it caused a minor smallpox infection; it was well known that once you had had smallpox, and recovered, you could never get it again. However, since it did involve infection with the actual virus, full-blown cases of smallpox could result. The advantages outweighed risks, and and after the remarkable Lady Mary Wortley Montagu observed variolation in Constantinople in 1717, she campaigned to institute the practice in Britain.
The disadvantages of variolation were well known by Edward Jenner, a country doctor in Gloucester who was a careful observer of all forms of nature. He observed and experimented with cuckoo eggs, for instance, documenting how cuckoo chicks hatch early and expel the other rightful eggs from the nest. His paper was published by the Royal Society, of which he was made a fellow. He had also made observations on hedgehog hibernation, and more to the medical point, he painstakingly autopsied hearts of patients who had died of angina, observing that indeed there was hardening of the arteries that supplied blood to the heart muscle.
It was Jenner who hypothesized that milkmaids got a related but relatively harmless disease, cowpox, and that it protected them from smallpox. Although there is evidence that others had had this idea, Jenner was the one to conduct an experiment to test the hypothesis. In 1796, he took a small amount of fluid from the blisters of milkmaid Sarah Nelmes, and inserted them into the skin of the eight-year-old boy James Phipps, the son of his gardener. James had mild cowpox symptoms, and recovered; when Jenner variolated him later with smallpox, James showed the slight reaction of someone who had already had the disease. (Jenner has been accused of putting the boy at risk with the variolation, but it was a standard treatment at the time.) Jenner had shown, scientifically, that cowpox was protective and that it could be transferred from one person to another.
Even in the eighteenth century, though, more was needed. Jenner had to repeat his experiment to show that the vaccination worked in other cases as well. Just as important, he had to publish. Even then, there was a peer review system, and it mattered. The Royal Society received his paper, judged (probably correctly) that more work needed to be done with more trials, and did not publish it. Jenner did do more trials, and documented them in an updated report of his results, but he did not submit it to the Royal Society. Instead, he published it himself, assuring by publication (even if it were not peer-reviewed) that he would get credit for his insight and procedure.
Jenner was to promote his vaccinations for the rest of his life, and because they worked, they became a standard of treatment. Britain was to ban variolation and to pay for vaccinations. The procedure swept Europe, and was taken overseas. There was no reliable refrigeration, and so getting the vaccine to distant lands was done by a "human chain" of arm-to-arm vaccination. A child would be vaccinated before going on a voyage, and along the way a few days later, pustular material was collected from the emergent smallpox lesions, and that material would be used to vaccinate the next in line, and so on until the ship landed and the last child in the chain could supply vaccine for the new world. Thomas Jefferson, who in 1801 wrote admiringly of the discovery of vaccination, designed an insulated package to keep the vials of vaccine cool in shorter travels, and when the local physician was too busy to do the vaccinations, the president himself did them.
Jenner dreamed of eradicating smallpox, and his dream came true, a century and a half after his death. Rhodes describes how there were protesters against the procedure, and how difficult it was for vaccinators to get to the wilds of India and Africa to get everyone vaccinated. We even know the identity and name of the last person to get a wild case of smallpox. The eradication, while undoubtedly a good thing for all humans, comes with a bit of worry. Nowadays, fewer and fewer people have had contact with the illness or any vaccine, so that if smallpox were to come back, it could be as devastating to the world as it was to the indigenous peoples visited by Europeans carrying the virus. And though a natural comeback of the disease is extremely unlikely, there are still stocks of smallpox virus, supposedly kept under heavy guard. It is scary to read that in the former Soviet Union smallpox bomblets were once considered a possible weapon, and it is still scary that some disillusioned or sociopathic scientist might grab himself some vials and let the plague lose on the world again.
We are making some progress in eliminating polio, another viral disease covered here. Polio was so feared and the 1955 announcement of the results of the field trial of the Salk vaccine was so anticipated, that when the report revealed that the vaccine was effective, people honked their horns and rang their church bells. Polio is almost eradicated, but is still hanging on in parts of the world, in no small part because of stupid violence and superstition against those sent out to do the vaccinations. Other illnesses considered here include flu, a viral disease of annual changeability, and HIV, tuberculosis, and malaria, for which vaccines are hoped but are far from being realized. This is a fascinating book that tells an inspiring story in the history of medicine, and also gives a good primer about how viruses, vaccines, and immune systems work. Vaccines have always had a risk connected to them (and protesters to take advantage of it): they involve exposing healthy people to prepared germs. The risk is slight, but it is not zero. The benefits, however, are immeasurable, and anyone who doubts it ought to read this book.