This piece, “Science Says: Immunizations Work" appeared on page 20 of the Spring 2025 issue of Chicago Life Magazine.
Immunizations have saved more human lives by far than any other medical intervention. Yet today the more than two centuries of solid science that stand behind immunizations is being questioned, people aren’t getting vaccinated and epidemics are looming. Trust the science. Get vaccinated.
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Four years of medical school followed by intense postgraduate training were pretty much all about hard science and how to apply those principles to patients and populations. As a physician, no matter the patient, no matter the problem, I always look first for a plausible scientific explanation for what has gone wrong and hopefully, how to fix it. I'm focusing here on vaccination because I believe the American public desperately needs its faith bolstered in vaccination and in science in general.
Nowhere is it clearer that vaccines work than in the story of smallpox, a disease that in the last 100 years of its existence killed an estimated 500 million people. Starting with the first inoculation performed by Edward Jenner in 1796 on up to near-global immunization in the 20th Century, we can thank the vaccine for the fact that smallpox virus has not infected a single human being on this planet since 1977, when the last case turned up in Somalia. Nobody even vaccinates against smallpox anymore (except some militaries in case this deadly agent is weaponized).
A foundational principle of the statistical methods that underlie much of science is that, all else being equal, the larger a group studied the more reliable the results. When there is data on 1 million subjects that indicates the protection rate of a vaccine is 95% it means a whole lot more than when there were just 100 subjects in the study. Because immunizations are given to large swaths of the population and infection, vaccination and complication reporting is widespread, studies of immunizations generally collect a great deal of data that, if well processed, results in high scientific credibility of a study's conclusions.
There is no medical intervention that works 100% of the time, not even smallpox vaccine. Ninety-five percent of people who are vaccinated would not come down with the illness if exposed to an active case. One or two out of a million people inoculated died of severe complications of the vaccine. That's 95%, not 100% protection, and one or two, not zero complications out of a million.
In general, the further results are from perfectly ideal, the more room there is for discussing the desirability of an intervention. In the days when smallpox was rampant, choosing vaccination should have been a no-brainer.
Toward the other end of the scale from smallpox vaccine is influenza vaccine, estimated to provide only 40% to 60% protection in its 2024-25 iteration. That number is so low because from year-to-year vaccine manufacturers have to guess at the chemical makeup of the ever-changing virus before it re-appears in the following flu season. Serious complications of flu vaccination are around one life-threatening allergic reaction plus one or two cases of Guillain-Barré, a debilitating neurologic disease, per million doses administered. Many recipients do get sore arms or mild fevers that resolve quickly. In the 2023-24 flu season 28,000 influenza deaths were reported in the US. You do the calculating about whether you're going to get a flu shot. I get one every year.
Then there's COVID, a disease so new, with vaccines against it that are even newer, caused by a virus that is at least as changeable as influenza. I won't begin to wade into how to calculate the value of COVID shots to a particular individual at a particular moment in time. As a rule I go along with the best (admittedly fallible) experts at the CDC and recommend vaccination when they do.
Between smallpox and influenza, there's polio. Enormous amounts of data have been collected to show high effectiveness and low complications of the vaccine, thanks to which polio incidence in US children showed a 10-fold drop, from 58,000 in 1955, the year it was released along with mass immunization programs, to 5,600 just 2 years later. Polio is a devastating disease, causing lifelong paralysis in one or more limbs and sometimes in breathing muscles, leading to death. There have been no outbreaks in this country since 1979. But polio still occurs in the less-developed world and could come back here as vaccination levels wane. I cannot imagine not protecting my child from polio.
Beginning in the 1930s credible population studies that linked smoking to lung cancer began appearing in the medical literature. Evidence continued to pile up at an accelerating pace about lung cancer, emphysema, heart disease, throat cancer, and multiple other devastating conditions associated with smoking. In 1954 the major American tobacco companies began an intensive public relations campaign that became the template for anti-science PR. “A Frank Statement To Cigarette Smokers,” was anything but frank. It was designed to cast doubt on the solid science that associated smoking with serious disease. Undaunted, the Surgeon General issued a definitive statement about the health consequences of smoking in 1964. The next year mandatory health warnings appeared on cigarette packs. It wasn't until 1998 that the industry admitted in the Master Tobacco Settlement that indeed smoking was bad for health.
It is not hard to see what led the tobacco moguls to discredit medical science in the public's mind. (Though I wonder how they looked themselves in the mirror.) Their profits have always depended on how much product they sold.
It is harder to pinpoint where anti-vax propaganda originates. Some of it comes from outside of scientific medicine. I remain open to alternative medicine, so long as it doesn't interfere with something that, as a trained scientist, I know really works. Sometimes alternatives are effective where the kind of medicine I practice isn't. Not so for vaccination.
I suspect there are other, more sinister forces behind the anti-vax movement. Among them are people who understand that creating doubt about real facts makes it easier to believe what Kellyanne Conway called “alternative facts,” thereby ungrounding reality and making us more manipulable.
Don't listen to the anti-vaxers, no matter their motivation. IMMUNIZATIONS WORK. They prevent huge amounts of illness and death while causing very, very few health problems. Talk to a healthcare provider who is grounded in science about which immunizations are right for you and your family. Me and mine take them all.
