Medical history provides numerous examples. Bloodletting was once considered an appropriate treatment for a wide range of illnesses. Thalidomide, diethylstilbestrol, and frontal lobotomy were all accepted medical practices before evidence demonstrated their serious limitations or harmful effects. These examples remind us that medical practice must always remain subject to scientific scrutiny.
But scientific scrutiny does not mean that established medical practices should be abandoned simply because a new hypothesis has been proposed. There is an important difference between raising a scientific question and having scientific evidence sufficient to change clinical practice. Anecdotal observations, individual experiences, and preliminary findings can be extremely valuable. They may identify an unexpected association or raise a legitimate hypothesis that deserves investigation. But they are generally the beginning of the scientific process, not the end of it.
If, for example, there are observations suggesting that administering multiple childhood vaccines together could produce an undesirable inflammatory or immune response, that possibility deserves to be studied. The appropriate response is neither to dismiss the observation nor immediately to change the vaccination schedule. The appropriate response is to formulate the question, conduct rigorous research, and determine whether the proposed effect actually exists and whether it is clinically meaningful. This is the foundation of evidence-based medicine.
Whenever feasible, randomized, well-designed clinical research should be used to test established medical practices and determine whether they continue to provide the expected benefits and risks. Randomization helps minimize the influence of confounding factors and bias and allows us to distinguish an actual treatment effect from associations that may occur by chance or because of other differences between patients. Evidence-based medicine should not be used merely to prove that new ideas are wrong. It should also be used to confirm that existing practices are right.
If rigorous research demonstrates that an established practice provides meaningful benefit with an acceptable risk, we should be willing to continue that practice, even when questions have been raised about it. Conversely, if high-quality evidence demonstrates that traditional practice is ineffective or harmful, physicians should be willing to change it. The standard should therefore not be whether a practice is old or new, conventional or unconventional, popular or controversial. The standard should be the quality of the evidence supporting it.
This principle is particularly currently important when considering changes to established childhood vaccination schedules. Vaccination recommendations are not based upon a single study or an individual physician’s opinion. They are the product of accumulated scientific evidence, clinical experience, epidemiologic data, ongoing safety monitoring, and evaluation by experts in infectious disease, pediatrics, immunology, public health, and other relevant disciplines.
New evidence may demonstrate that a vaccine should be administered at a different age, that doses should be added or removed, that vaccines should be combined differently, or that an alternative strategy produces better outcomes. If high-quality evidence demonstrates such a benefit, our medical organizations and physicians should be prepared to change established recommendations.
As physicians, our responsibility is to maintain an appropriate balance between healthy skepticism and scientific discipline. We should question accepted practices. We should investigate unexpected findings. We should encourage research that challenges prevailing assumptions. And we should be willing to change our recommendations when credible evidence demonstrates that change will improve patient outcomes. But we should also recognize that decades of accumulated evidence cannot appropriately be dismissed by a single observation, an untested hypothesis, or an appeal to intuition.
Question the practice. Formulate the hypothesis. Study it rigorously. Analyze the evidence. Reproduce the findings. Then change practice if the evidence warrants it. That is not simply a philosophy for evaluating vaccines. It is the foundation of evidence-based medicine and one of the reasons modern medicine has been able to advance so dramatically. Our obligation as physicians is not to defend medicine’s past or to embrace every new idea. It is to follow the evidence.
All the best,
Mark J. Adams, MD, MBA, FACR
MSSNY President
