...by the time laboratory medicine came effectively into the picture the job had been carried far toward completion by the humanitarians and social reformers of the nineteenth century... When the tide is receding from the beach it is easy to have the illusion that one can empty the ocean by removing water with a pail.

In general, medical measures (both chemotherapeutic and prophylactic) appear to have contributed little to the overall decline in mortality in the United States since about 1900-having in many instances been introduced several decades after a marked decline had already set in and having no detectable influence in most instances. More specifically, with reference to thosefive conditions (influenza, pneumonia, diphtheria, whooping cough, and poliomyelitis) for which the decline in mortality appears substantial after the point of intervention-and on the unlikely assumption that all of this decline is attributable to the intervention-it is estimated that at most 3.5 percent of the total decline in mortality since 1900 could be ascribed to medical measures introduced for the diseases considered here.

These conclusions, in support of the thesis introduced earlier, suggest issues of the most strategic significance for researchers and health care legislators. Profound policy implications follow from either a confirmation or a rejection of the thesis. If one subscribes to the view that we are slowly but surely eliminating one disease after another because of medical interventions, then there may be little commitment to social change and even resistance to some reordering of priorities in medical expenditures. If a disease X is disappearing primarily because of the presence of a particular intervention or service Y, then clearly Y should be left intact, or, more preferably, be expanded. Its demonstrable contribution justifies its presence. But, if it can be shown convincingly, and on commonly accepted grounds, that the major part of the decline in mortality is unrelated to medical care activities, then some commitment to social change and a reordering of priorities may ensue. For, if the disappearance of X is largely unrelated to the presence of Y, or even occurs in the absence of Y, then clearly the expansion and even the continuance of Y can be reasonably questioned. Its demonstrable ineffectiveness justifies some reappraisal of its significance and the wisdom of expanding it in its existing form.

We had accepted some half-truths and had stopped searching for the whole truths. The principal half-truths were that medical research had stamped out the great killers of the past – tuberculosis, diphtheria, pneumonia, puerperal sepsis, etc. – and that medical research and our superior system of medical care were major factors in extending life expectancy. The data on deaths from tuberculosis show that the mortality rate from this disease has been declining steadily since the middle of the 19th century and has continued to decline in almost linear fashion during the past 100 years [till 1970]. There were increases in rates of tuberculosis during wars and under specified adverse local conditions. The poor and the crowded always came off worst of all in war and in peace, but the overall decline in deaths from tuberculosis was not altered measurably by the discovery of the tuberculosis bacillus, the advent of the tuberculin test, the appearance of BCG vaccination, the widespread use of mass screening, the intensive anti-tuberculosis campaigns, or the discovery of streptomycin. It is important that this point be understood in its completeness. The point was made years ago by Wade Hamptom Frost, and more recently by René Dubos, and has been repeatedly stressed through the years by many observers of the public health. Similar trends in mortality have been reported with respect to diphtheria, scarlet fever, rheumatic fever, pertussis, measles, and many others.

In conclusion, the largest historical decrease in morbidity and mortality caused by infectious disease was experienced not with the modern antibiotic and vaccine era, but after the introduction of clean water and effective sewer systems.

Vaccination does not account for the impressive declines in mortality seen in the first half of the century ... nearly 90% of the decline in infectious disease mortality among US children occured before 1940, when few antibiotics or vaccines were available.