Compared to what it could be. For example, malaria is still a huge issue in much of the world -- and it's fixable with 20th century technology, at least in countries that have their basic shit together. The USA used to have a really nasty malaria problem, especially in the South; after the National Malaria Eradication Program (1947–1951), the malaria problem was essentially gone. Some other countries have done the same with even more challenging geography and climate.