Without vaccine mandates, diseases spread. Communities get sick. People die.
Once upon a time, HHS eradicated smallpox and polio. Now, with RFK Jr at the wheel, it’s doing PR for measles.
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Vaccines are one of the most effective and life-saving scientific technologies in modern medicine. They save lives, prevent suffering, and spare health systems from collapse. But they only work to control communicable illness when enough people in a population get them. That proportion can be as high as 95% for highly contagious disease-causing microbes (pathogens).
Governments in the US have been co-opted by anti-science profiteers trying to roll back decades of progress attributed to these life-saving medicines.
I won’t lie: it’s been very hard seeing my life’s passion (and career) be erased by people without any credible expertise who lie without consequence. This week in particular has been a lot for me and fellow biomedical scientists.
Yesterday, RFK Jr spent another day lying to Congress, the very people who installed him as head of HHS and yet still don’t want to hold him accountable. I’ve written about his history of lies here, here, here, here, and here (there are more, just head to the section of ImmunoLogic tagged “RFK JR”).
Also this week, Joseph Ladapo and Ron DeSantis announced that Florida will remove vaccine requirements for schools. Ladapo went so far as to liken vaccine mandates to slavery — a grotesque, and false — comparison. As you’d expect, there was a predictable deluge of “health freedom” activists cheering this escape from “tyranny.”
Removing vaccine requirements doesn’t give us “freedom” — it removes freedom by making us vulnerable to preventable illness and worse health.
Yesterday, HHS (under the control of RFK Jr) endorsed religious and personal belief exemptions from vaccines—normalizing the false notion that there should be some sort of ideological objection to these life-saving medicines.
These moves will be devastating. Not just for kids in Florida impacted by the loss of vaccine mandates—for entire communities across the country (and potentially the world). We know what happens without vaccine mandates—it’s why they exist today.
Anti-vaccine rhetoric is a top ten global health threat. We will all face the deadly consequences of these decisions.
Vaccine mandates eliminated polio and smallpox
Before vaccines, polio devastated tens of thousands of people every year, causing paralysis, limb deformities, and death. The development and introduction of polio vaccines in the 1950s opened the door to a world where that wasn’t the case.
By 1963, 85% of children younger than 10 had received as least one vaccine dose, driven by widespread and enthusiastic vaccine campaigns. By the 1960s, every state had polio vaccine mandates for school, and polio cases across the country had plummeted to just 161 in a year. By 1979, the US had eliminated polio, and today, almost the entire world is free from it, thanks to vaccine mandates (only two countries have endemic polio today).
Smallpox was fully eradicated from the planet because of largescale vaccine campaigns and global mandates. In the US, smallpox vaccination was required for schools in states as far back as 1850, with city-level mandates starting in 1827. A small outbreak of 12 cases in New York City in 1947 spurred an effort which vaccinated 6.35 million people in 3 weeks and stopped the outbreak.
You might be thinking, 12 cases seems so small for such an effort. But when you’ve actually witnessed the devastation a disease can cause, you understand the importance of vaccination. Today, we are privileged to be shielded from much of that precisely because of how effective vaccines are. The irony, right?
When mandates disappear, preventable illness and death spreads.
Diphtheria is a contagious and deadly respiratory illness caused by the bacterium Corynebacterium diphtheriae with a mortality rate up to 10%. To stop the spread of diphtheria, 85-90% of the population must be vaccinated.
Diphtheria had been controlled in the Soviet Union after mandatory vaccination campaigns began in the 1950s. By the late 1970s, vaccination rates exceeded 90% and USSR saw only a few thousand cases per year among a population of 280 million, underscoring the success of largescale vaccine mandates.
The Soviet Union collapsed in the late 1980s through early 1990s. Public health systems also collapsed, vaccine production and distribution halted, and enforcement of school and workplace vaccine mandates disappeared. Growing distrust of the government exacerbated problems, and vaccine coverage plummeted to 60-70%, especially among adults who missed early vaccine campaigns.
The result? The largest diphtheria epidemic the world had seen since the 1950s. Between 1990 and 1998, the newly independent states reported 157,000 cases and 5,000 deaths. The epidemic only ended after emergency mass vaccination campaigns deployed by the WHO and partner organizations—essentially reinstated mandates—brought coverage back above 90%.
This case shows that even diseases on the brink of elimination come rushing back when vaccine mandates disappear.
Weak vaccine mandates function as no mandates at all.
And it wasn’t just the Soviet Union. Whenever mandates are weak or riddled with loopholes, history repeats itself. In California, school vaccine “requirements” once allowed parents to opt out for any personal belief. In some counties, kindergarten MMR coverage plummeted to 50–60% — well below the 95% needed to keep measles at bay.
Guess what happened? A measles outbreak started at Disneyland in 2014.
The first case was reported in an unvaccinated 11-year old child hospitalized in early January 2015 and rapidly spread across 7 states, Mexico, and Canada. In the US, several hundred cases were reported with a hospitalization rate of 20%. While most US cases were among unvaccinated Californians, a single case from Disneyland imported into Canada led to 150 measles cases among an unvaccinated religious community.
Nearly all cases were in unvaccinated people, 76% of whom cited “personal beliefs” as to why they were unvaccinated. California passed SB 277 in 2016, removing the personal belief loophole from vaccination requirements. By the 2017-2018 schoolyear, kindergarten MMR vaccine rates were up to 97.3%, a level needed to keep measles at bay.
Here, a weak mandate functioned as no mandate at all. Voluntary vaccine compliance is not good enough. In every instance through history where vaccine requirements don’t exist, the predictable happens: an outbreak occurs, illness spreads, and in many cases, people die.
Religious exemptions led to dead children in Philadelphia
If California in 2015 showed us the danger of “personal beliefs,” Philadelphia in 1991 illustrated the the cost of “religious freedom.”
Two fundamentalist churches in the city (Faith Tabernacle Congregation and First Century Gospel Church) not only refused vaccines but rejected all medical care. They didn’t believe in doctors, and promoted the deadly idea of “prayer for healing.” The entirely unvaccinated student bodies at their religious schools fueled a citywide outbreak of measles, starting in late 1990.
Over 1,424 measles cases occurred in Philadelphia, with 486 in the congregations themselves. Nine children died in those communities, a 1.2% case-fatality rate in a city where measles should not have been fatal at all. The reason for that? Because only one of the children that died received any medical care.
A court order was enacted, citing the 1944 US Supreme Court decision Prince v. Massachusetts (parents’ religious beliefs do not extend to denying lifesaving medical care for children). Without legal enforcement of vaccinations, more children would have died.
And yet yesterday, in the year 2025, RFK Jr’s HHS is promoting religious and personal belief exemptions as if we don’t already know where that road leads.
We have literal case law, decades of history, and data clearly showing that religious objections don’t trump a child’s right to health. And yet the nation’s top health agency is platforming exactly that excuse. Buckle up for a repeat of Philly 1991, folks.
Vaccine mandates improve trust in science and participation in public health
In 2018, France proved this. Up till then, there were only requirements for diphtheria, pertussis, and poliomyelitis (DT and IPV), and France had one of the highest rates of vaccine hesitancy in the world. On January 1, 2018, they expanded mandates to include vaccines to protect against 8 additional diseases: Haemophilus influenzae type B (Hib), Pertussis, Hepatitis B, Measles, Mumps, Rubella (MMR), Meningococcus C, and Streptococcus pneumoniae.
The result was rapid and positive. Between 2016 and 2018:
Hepatitis B vaccine rates climbed from ~92% to 98%.
MenC (1st dose) increased from 39.3% to 75.7%.
MMR coverage for dose 1 increased from 87.3% to 93.0% and dose 2 increased from 82.2% to 88.9%.
But what was even more important: public doubts about vaccine safety and effectiveness improved. Concerns about vaccine safety declined from 41 to 23.7% and doubts about effectiveness fell from 17.3% to 12.5%. Normalizing vaccines through laws reduced hesitancy and improved confidence in them as health interventions.
This is what our government should be doing — not actively contributing to the legitimization of anti-vaccine lies. Mandates don’t just improve vaccine rates, they reshape public attitudes.
We don’t get herd immunity with vibes, polite reminders, or recommendations. We get there with mandates.
It would be great if merely encouraging people to do the right thing for everyone in a functioning society (are we a functioning society anymore, though?) was enough to get vaccination rates to levels we need to control contagious illnesses.
But humans don’t work that way. Humans are bad at risk perception, especially if a threat feels far away or abstract. If a benefit of an action is collective, people often free-ride and rely on others. If a risk is invisible (like viruses and bacteria are without microscopes), it’s even easier to ignore it. And if the risk is in the future? Now you’ve got the trifecta.
We’ve tried the voluntary vaccine recommendation approach throughout history. It doesn’t work. Vaccine rates don’t get to the levels they must to control outbreaks and the spread of preventable illness.
Mandates are necessary because humans are irrational and cannot appropriately assess risk. Many psychological factors lead to vaccine avoidance without requirements in place:
Free-rider mentality: People assume “everyone else will get vaccinated, so my kid will be safe.” This works until enough people do the same. Then you’ve got low vaccine coverage where a single case of measles can spread to record-breaking levels. This literally happened in Texas this year, remember?
Optimism bias: This is the evergreen “oh, it won’t happen to me” mentality. Guess what? It inevitably does.
Psychological myopia (aka FAFO): This is so common we’ve got an acronym for it (yep, FAFO is “fuck around and find out”). People focus on immediate outcomes while ignoring or underestimating long-term consequences. A vaccination “feels” more risky than an illness you might get in the future if you remain unvaccinated. Plus, with optimism bias, you’re already confident that won’t happen to you.
People are inherently selfish: Not a judgment, a scientific reality. That’s why fitness in biology measures an organisms’ ability to survive and reproduce: the evolutionary every man for himself. But it requires conscious effort for most people to consider those beyond their immediate sphere. Without mandates, people try to frame vaccines as a “personal choice,” ignoring that your choice impacts others. Vaccines control communicable diseases: illnesses that spread among people. When you don’t vaccinate, your choice puts everyone you interact with at risk: babies, cancer patients, the elderly, your neighbor with a transplant.
Mandates remove this psychological conflict. They turn vaccination from optional to the expectation of living in a society. You live in a society, right? We all do things to participate in a society, right? Taking our trash out, following traffic rules, not dumping raw sewage in the street. Vaccination is part of that collective responsibility too.
Vaccine mandates aren’t tyranny. They’re wellness behaviors that keep society safe.
They’re why you don’t know anyone who died of smallpox.
They’re why playgrounds aren’t filled with kids in braces from polio.
They’re why a puncture wound isn’t a death sentence.
Remove them? History repeats: diseases spread, illness follows, and people die.
And that’s the road RFK Jr., Marty Makary, Ron DeSantis, Joseph Ladapo, the MAHA movement, and their enablers are steering us down as they co-opt the very agencies that once led the world in eradicating smallpox and polio.
RFK Jr. and HHS promoting personal belief and religious exemptions isn’t protecting freedom. It’s protecting viruses. Congratulations: our tax dollars are paying for HHS to run PR for preventable illnesses.
Now, more than ever, we all must join in the fight for science.
Thank you for supporting evidence-based science communication. With outbreaks of preventable diseases, refusal of evidence-based medical interventions, propagation of pseudoscience by prominent public “personalities”, it’s needed now more than ever.
More science education, less disinformation.
- Andrea
ImmunoLogic is written by Dr. Andrea Love, PhD - immunologist and microbiologist. She works full-time in life sciences biotech and has had a lifelong passion for closing the science literacy gap and combating pseudoscience and health misinformation as far back as her childhood. This newsletter and her science communication on her social media pages are born from that passion. Follow on Instagram, Threads, Twitter, and Facebook, or support the newsletter by subscribing below:
Oof, we are sooo screwed