With a pandemic putting much of the world into lockdowns or quarantine, it might seem counterfactual for anyone to be optimistic about the future of diseases and the medical responses to them. Modern travel gives diseases that mutate and cross the species barrier from animals to humans the ability to spread rapidly, but modern medicine increases the speed and range of our responses to them. The development and testing of several vaccines against the coronavirus achieved within a single year a process that has usually taken 5 - 10 years. Humankind will emerge from the pandemic far better equipped to deal with new diseases when they appear than it was before. It has coped with Ebola, SARS, H5N1 bird flu, and MERS camel flu, and AIDS is no longer the death sentence it once was.
Of the diseases that ravaged previous populations, smallpox has been rendered extinct by vaccination, tuberculosis is treatable, and polio is on the verge of extinction in the wild. Even the ancient enemy, malaria, is within range as a variety of methods to combat it is being developed, and its extinction by mid-century looks very likely.
Heart disease used to be the big feared killer, but many cases of it are now treatable by drug therapy, angioplasty or bypass operations. This has led to various cancers taking its place as more people survive it. Cancers are increasingly more treatable than before, and it is likely that nanotechnology will give medicine the edge by locating cancer cells much earlier in the body, and targeting individual cancer cells to destroy them.
The resources and effort going into the early detection and treatment of the different forms of dementia and their reversal suggest that before long we will have a range of procedures to halt and reverse the build-up of the plaques and other conditions that induce it.
The principal cause for optimism about medicine in the future derives from work being done at the genetic level. Gene therapy and gene editing have brought the possibility of disabling or editing genes associated with inherited diseases, and even of editing genes to confer immunity against subsequent life-threatening conditions. Much of this type of procedure can be done in the womb, so the child will be born with the advantages it brings. Gene therapy might even offer ways of slowing down the process of ageing.
Despite the pandemic, medicine is continuing to advance at an increasing range, extending our ability to cope with the conditions that nature sends our way. To those who say the world will never be the same again, the best response is that this is correct. It will be better.