Thirty-five years ago, as a pediatrician working at an Indian Health Service (IHS) hospital on the Navajo Nation, I played a small part in defeating a disease few readers today have heard of. In a two-year trial involving more than five thousand infants, researchers from the Johns Hopkins University Center for Indigenous Health tested a new vaccine against Haemophilus influenzae Type b (Hib), then a common childhood infection. Across the nation, Hib disease typically struck children five and under as an aggressive but treatable infection. For unknown reasons, however, Native children usually fell ill in the first six months of life with Hib’s most devastating form: bacterial meningitis. Even with swift and proper treatment, Hib meningitis left twenty percent of its survivors with long-term brain dysfunction ranging from hearing loss to severe developmental delay. When I arrived on the Navajo Nation in 1989, standard practice was to administer an existing Hib vaccine at eighteen months, the earliest that particular vaccine offered protection. While this eased the burden of Hib disease among older children nationwide, it did little for those who fell ill far earlier. The new vaccine Johns Hopkins tested for safety and efficacy was given at two and four months of age, soon enough to protect the families we saw in clinic from the ravages of Hib meningitis. My colleagues and I had little difficulty persuading parents to join the study. Most knew a relative whose life had been drastically altered by Hib disease, and they wished to spare their children. 

It worked. When data from the study revealed the new vaccine to be safe and highly effective, the medication was offered to all our eligible patients. An overwhelming majority of Navajo and Hopi parents agreed to immunize their children, and Hib disease quickly vanished. This response was driven in large part by community awareness of the serious consequences of Hib disease as well as the safety and effectiveness of other public health interventions – including vaccines – researchers from Johns Hopkins had tested there. Like parents across the United States in the 1950s who dreaded the return of polio each summer, the parents of my patients had seen family members sicken or die from a disease they wanted to protect their children against. As with polio, those familiar with the lasting effects of Hib disease not only welcomed the new shot, they encouraged other parents to do likewise.

That some now fear polio vaccine more than paralytic polio disease is in part a consequence of the vaccine’s success. In 1952, the year before Jonas Salk announced the development of his polio vaccine, nearly sixty thousand new cases were reported, with more than three thousand deaths. By 1957, new polio cases had decreased by 90 percent. By 1994, the Americas – North and South – were polio-free. Since then, on the rare occasion that cases of polio are reported in the United States, they can be traced to travelers exposed to the disease somewhere in the developing world. Anyone who has seen a newly diagnosed polio victim, however, is unlikely to dismiss the disease as a minor childhood inconvenience.

Starting in 1950, childhood immunizations transformed the treatment of many other infectious diseases as well, dramatically increasing life expectancy, reducing child mortality, and virtually eliminating deaths from measles, pertussis (whooping cough), polio, tetanus, and Hib. Yet, as with any medicine, there has never been a time when vaccines were free from safety concerns. In 1955, for example, Cutter Laboratories, one of the first companies licensed to manufacture Salk’s vaccine, inadvertently released vials containing live polio virus. The so-called “Cutter incident” caused thousands of infections and ten deaths.

Though manufacturers raised their production surveillance and testing standards, a steady stream of civil suits continued, sometimes by persons with conditions not demonstrably related to vaccination. In 1986, Congress passed the National Vaccine Injury Compensation Act, paying people claiming injury after a vaccination even without scientific evidence that the vaccine caused the injury. The act led to the establishment of the Vaccine Adverse Event Reporting System (VAERS), a surveillance database that collects information on effects following (but not necessarily caused by) vaccinations. Anyone, not just health care providers, can file online through the VAERS website. Reports of adverse events ranging from a sore arm to unexpected death are then analyzed to monitor known side effects or to identify unexpected problems associated with new vaccines. In 1999, for example, VAERS data detected a rise in bowel obstructions among children who had received a newly approved rotavirus vaccine. Further research confirmed the link and the vaccine was suspended.

Vaccine skeptics and opponents often cite raw VAERS data without evidence that an alleged injury was due to the vaccine. A 2006 external review of the database concluded that attorneys were deliberately skewing the system, filing an increasing number of serious events for purposes of litigation. Even though anecdotal reports from VAERS data does not prove that a vaccine causes a specific injury, anti-vaccine organizations used the database to support claims that Covid-19 immunizations were unsafe. Other vaccine opponents claimed Covid-19 vaccines were approved for use without proper safety testing. It’s true that the Trump administration accelerated the development and approval process of Covid-19 vaccines during the pandemic. Nevertheless, safety trials on the first vaccine to receive emergency use authorization (Pfizer’s and BioNTech’s Comirnaty) enrolled forty-six thousand participants in a rigorous placebo-controlled study, more than nine times the number of infants recruited for the HiB vaccine trial mentioned above.) As with many medications undergoing pre-approval safety testing, some extremely rare but serious conditions were reported, ranging from allergic reactions to inflammation in the heart muscle or heart lining. A 2024 review of ninety-nine million recipients of various Covid-19 vaccines largely confirmed these results. How these data are interpreted, however, depends on what assumptions and judgements one brings to bear. Advocates favorably compare the rarity of serious untoward events to the estimated number of hospitalizations and deaths prevented by vaccination. Opponents argue that any serious adverse event, whether proven to be vaccine related or not, is unacceptable. Parents of a child who suffers from a rare but serious vaccine side effect may agree, National Vaccine Injury Compensation Act funds notwithstanding.

Taking any medicine comes with risks. Some people are harmed by things designed to heal. Vaccines are no exception. The oral polio vaccine introduced by Albert Sabin around 1960, for instance, contains weakened, live poliovirus that induces a protective response in persons with a normal immune system. Infants with compromised or defective immunity, however, may develop polio disease – usually mild but sometimes severe. Because of this, the United States has not used the Sabin vaccine since 2000, though in developing countries it still plays an important role in polio eradication efforts. 

Vaccines differ from most other therapeutic substances in one important way. The rare but serious health risks of a medication to lower cholesterol levels or blood pressure, for example, are limited to those who take it. The individual who receives a vaccine may benefit from the immune effects while accepting a small but nontrivial risk, yet the biggest beneficiary is the community. A community with high vaccination rates protects even those who, for whatever reason, are not immune by reducing the likelihood of exposure to infected persons – the phenomenon known as herd immunity. When the community’s immunity falls below a certain percentage, it’s only a matter of time and chance before the disease returns. Decisions to shield oneself or one’s child from a rare vaccine-related complication versus acting in communal solidarity are difficult enough when competing claims – some of them dubious – freely circulate on commercial and social media. The main flashpoint for conflict, however, lies in school or workplace vaccine mandates.

As many parents know, schools are nearly perfect incubators for viral outbreaks, usually in the form of colds and flu-like illnesses. Preventing the spread of more serious infections like whooping cough and measles is the intent behind school vaccination mandates. Similarly, hospitals and related facilities mandate certain vaccines for employees to prevent patients from getting infected while receiving care. Parents, individual adults, health care providers, and public health professionals must weigh the concerns of the individual against the good of the community. Officials make vaccine recommendations prudentially, considering populations at greatest risk and using the best available scientific information. Most health care workers who have seen patients die from vaccine-preventable infections such as measles strongly support community vaccination efforts. Parents have a much more focused population in mind: their own children. For some parents, anecdotal reports of alleged vaccine-related injuries may appear more compelling than a mountain of actuarial data. Anti-vaccine sentiment – often fed by questionable information circulated on the internet – has lowered school-age vaccine rates sufficiently for measles, whooping cough, and other infectious diseases to resurface. Choosing not to immunize, however sincere the motivation, puts oneself and others at risk.

For decades, vaccine recommendations have drawn on good science that proceeds slowly and cautiously, relying on careful study design, meticulous data analysis, modest conclusions, and subsequent confirmation by other researchers. Study reports undergo peer review before publication. Online misinterpretation, misinformation, and outright lies, on the other hand, spread like crude oil from a sinking tanker: slowly at first, and then in a fast-spreading mire. The enduring belief that the measles-mumps-rubella vaccine (MMR) causes autism began in what looked like scientific evidence until proved otherwise. In 1998, a British surgeon named Andrew Wakefield was lead author on a paper in the medical journal The Lancet linking the MMR vaccine to autism. Even before the paper was published, Wakefield appeared at a press conference, calling for suspension of MMR vaccination. What Wakefield failed to disclose was that he had already filed a patent application for a new, allegedly safer, single-shot measles vaccine, from which he stood to earn millions of dollars. From 2002 through 2004, several published papers showed no link between MMR and autism. In March of 2004, ten of Wakefield’s coauthors on the initial paper disavowed the study, and in 2010 The Lancet formally retracted the article after evidence emerged that Wakefield had falsified critical details.

By then, Wakefield’s elaborate fraud had already done much damage. Taking his initial report at face value, many providers abandoned MMR. Vaccination rates declined, followed by increases in measles and mumps cases. Wakefield remains polarizing, condemned by scientists and physicians for fraud while praised by vaccine opponents for standing up to a corrupt medical establishment and “Big Pharma.”

As a pediatrician and a parent, I have little love for corporations that, whatever their other intentions, maintain a fiduciary responsibility to stockholders. Attention to product safety is, of course, an element of that responsibility and vaccines rarely make the list of the world’s most profitable drugs. From year to year, the top money-makers are almost always recently patented medications designed to treat chronic diseases in adults. When a corporation is sued over an alleged vaccine-related injury, it either passes the cost of these legal battles on to providers and patients or gets out of the vaccine business altogether. Of the twenty-six vaccine manufacturers operating in 1957, only four remain today.

For all that vaccines have done to reduce infectious disease burdens, “Big Pharma” will always have foes as long as schools and employers mandate certain vaccines. Nothing similar applies to personal injury law firms within “Big Legal,” or the social media empires within “Big Tech.” Abandoning mandates, however, all but guarantees increased rates of vaccine-preventable disease and death, especially in children.

In current debates about vaccines, demonization upstages thoughtful deliberation. In this contentious environment, how is a parent to choose what’s best? My first recommendation is to talk to your child’s health care provider or a trusted physician. Voice your concerns and ask questions. Even within the cramped time limits dictated by the health care system, a good provider can address your concerns and direct your attention to reliable sources of scientific, fact-based information.

Though I am now retired from clinical practice, I have cared for very ill patients during a measles epidemic. Some died of the disease. I want to protect all children from that fate. Yet whenever a parent, bewildered by conflicting information, expressed doubts about the MMR, I encouraged a conversation, in which I responded to their questions before recounting my experience. If we did not find common ground on the MMR, I respected their decision while promising to revisit the matter on subsequent visits. If parents wished to share what they had heard, read, or watched online, I promised to check it out.

My second recommendation is to weigh all vaccine-related information for accuracy, reliability, and lack of bias. The politically charged atmosphere in which public health policy is currently discussed and implemented makes this more challenging than it ought to be. Few non-professionals know how to read scientific papers critically, so some degree of trust is necessary. Yes, corporations have a history of suppressing scientific evidence that could hurt their bottom line. Flagrant examples include tobacco companies and smoking-related cancers, and fossil fuel companies and climate change. At the same time, personal-injury attorneys, anti-vaccine crusaders, and political demagogues often quote dubious studies, misrepresent data, and take carefully worded scientific statements out of context. Beware of outlandish claims, sweeping accusations, and grand conspiracy theories.

Finally, when you meet someone whose views on vaccines and public health mandates differ markedly from your own, remember that most people most of the time do what they think best, based on their experience and knowledge. Take a page from Ignatius Loyola’s Spiritual Exercises and try to put a good interpretation on the other’s statement rather than condemn it out of hand. When you can’t interpret it favorably, Ignatius adds, ask how the other person means what he says and, if necessary, correct misinformation in a spirit of truth and love. Not every opinion can be accommodated, but even the smallest patch of common ground may serve as a starting place – if not toward agreement, then at least toward mutual understanding. Dialing down the rhetoric in what passes for debate over vaccine safety and public health mandates is a necessary first step toward restoring trust.