Why We Don’t Start From Zero in Science and Medicine
Like modern systems, vaccine trials build on what we already know to reduce risk. Besides, we do have saline placebos for most vaccines.
In engineering, product development often follows a continuous improvement cycle, a process built on iteration, refinement, and data-driven progress. Each new model, system, or design builds upon the proven foundation of what came before.
When a car company releases a new vehicle, it doesn’t go back and test it against a car with no brakes or no airbags.
When an aerospace team upgrades an aircraft, it doesn’t remove radar, GPS, or emergency systems just to test the new version in isolation.
When tech companies launch new smartphones, they don’t compare them to rotary phones or blank circuit boards.
Instead, they ask:
Is this version faster, safer, or more efficient?
Does it improve on the current best system?
How does it perform within the full safety and performance architecture already in place?
What are the new risks introduced relative to the ones we already understand and have quantified?
That’s the principle of iterative design, where each new version is compared against the latest validated standard, not a baseline of nothing. Returning to square one would be inefficient, regressive, and in many cases, dangerous.
This is the same logic we apply in ethical medicine and vaccine development.
Vaccines, like engineered systems, undergo rigorous testing and refinement, but we don't go back to zero once a vaccine is proven safe and effective. Just like engineers don’t test new planes by removing their safety systems, vaccine researchers don’t keep comparing new candidates to a placebo once we have a working solution.
When a new vaccine is developed, it first goes through placebo-controlled trials, which are essential when there’s no existing prevention method. For completely new vaccine types, we often use inert placebos like saline (salt water). If one is trying to isolate side effects, active placebos are implemented. These contain all ingredients except the antigen or polysaccharide that generates an immune response in the vaccine.
We’re asking the foundational question:
Does this vaccine work better (and safer) than doing nothing?
Once that question is answered, once a vaccine has shown it can safely and effectively prevent disease, it becomes the standard of care. This is true for most medications.
From Placebo to Progress
At that point, new or updated vaccines are tested against the existing vaccine, not a placebo.
We ask:
Does this updated vaccine produce a stronger or longer-lasting immune response?
Does it have fewer side effects?
Is it more effective against emerging variants?
Can it be stored or delivered more efficiently?
These are active comparator trials, where the bar is no longer “better than nothing,” but “better than the best we have.”
Why Not Placebo Again?
Because going back to a placebo, especially in populations where a safe and effective vaccine already exists, would be unethical.
You wouldn’t deny passengers or pilots a collision-avoidance system, radar, autopilot, weather detection, or GPS in a plane just to test a new safety feature in a plane.
And we don’t deny people protection from deadly diseases just to reset the control group.
We don’t design or make a new aircraft by removing everything that keeps people safe in another.
We design and test them by comparing them to the current best version, with all its vetted safety features intact. That is why new designs usually retrofit older ones.
That's how you explore risk as a system.
Giving someone a placebo when a proven vaccine already exists would mean knowingly denying protection. That’s why for diseases like measles, polio, or COVID (post-2021), new vaccines are tested head-to-head against the established options.
Common concerns
Often, I hear the following concerns about vaccine trials:
“Why weren’t vaccine trials held longer?”
“What if side effects show up months or years later?”
Let’s break that down with science, ethics, and context.
First: Rare Adverse Events Need Big Numbers, Not More Time
Some side effects are extremely rare, like 1 in 100,000 or even 1 in 1,000,000.
These aren’t missed because trials are “rushed.”
They’re missed because no trial can enroll a million people up front.
This is where the Rule of Three comes in:
If a serious side effect happens in 1 in 1,000 people, you’d need about 3,000 participants to have a 95% chance of detecting even one case.
If it’s 1 in 100,000? You’d need 300,000 people.
That’s why we rely on post-marketing surveillance, the careful monitoring of vaccines after approval, across millions of real-world recipients.
But What About Long-Term Side Effects?
Here’s what’s critical:
Serious vaccine side effects almost always appear within 6–8 weeks.
Examples from vaccine history:
Oral Polio Vaccine → Paralysis (1 in 2.4 million) → Seen within 4 weeks
MMR → Immune thrombocytopenia (1 in 30,000) → Within 6–8 weeks
1976 Flu Vaccine → Guillain-Barré Syndrome (GBS), but GBS is 17× more likely from flu itself → Seen within 8 weeks
Yellow Fever Vaccine → Neurologic complications → Within 2–3 weeks
Anaphylaxis → Occurs within minutes, monitored on-site
So, extending trials beyond this window doesn’t help much in catching side effects, because the kinds of effects people worry about don’t appear months later out of nowhere.
What Trials Are Designed to Do
Vaccine trials are built to answer three main questions:
Does it work better than no vaccine or standard of care?
Answered by comparing to a control group with the introduction of a new vaccine, or against the standard of care (another vaccine).How well does it work?
This is the effect size, or vaccine efficacy.What are the side effects or risks?
This compares against doing nothing (placebo) or the standard of care (other vaccines).
COVID vaccine trials, for example, enrolled tens of thousands of people and ended after just a few hundred infections, not because that’s “too soon,” but because the difference between groups was massive.
A large effect size means fewer events are needed to confidently detect a difference.
If a vaccine reduces your risk by 90%, it doesn’t take long to prove that’s not just luck.
Placebo-controlled trials already exist
Most vaccines have been studied with a saline placebo.
These have then been used as control vaccines in trials for newer vaccines, as we already know that they are safe and effective. Newer vaccines that came later were then tested using these vaccines as a control group.
Vaccines that were studied with saline placebos include:
acellular pertussis
BCG
oral polio
Hib
measles
rubella
mumps
typhoid
Prevnar 7
pneumococcal polysaccharide vaccines
HPV
live flu
inactivated flu
COVID-19
cholera
dengue
Some vaccine trials even used unvaccinated control groups (not even a placebo).
What did the results show?
Just as anticipated, unvaccinated participants in the trials got sick more frequently than those who received the vaccine.
Risk as a System, Not a Snapshot
People often isolate one scary “what if?”, but risk isn’t binary.
It’s a dynamic system involving:
The disease risk itself
Known and theoretical side effect risks
Existing safeguards and surveillance
Your health status, behavior, and environment
What matters is not whether a vaccine is 100% safe, nothing is, but whether it reduces your overall risk in the system you live in.
When evaluating a new vaccine, we’re not just asking “Is this safe?” in a vacuum.
We’re asking:
How does this new option change the overall risk within the system we already understand?
Once you have data for existing safe and effective vaccines, you evaluate risk against that benchmark. We already know the benefits and side effects of the standard vaccine. That gives us a stable reference point, a risk baseline, from which to evaluate improvements or trade-offs in the new one.
And the answer, backed by both trial and real-world data, has been a resounding yes.
The Moving Target of Misinformation: How RFK Jr. Distorts Risk
RFK Jr. doesn’t evaluate risk honestly or systemically. Instead, he isolates risk to elicit fear, exaggerates it, and constantly shifts the narrative to keep doubt alive. His messaging isn’t about protecting public health; it’s about reframing inaction as cautionary wisdom and sowing distrust at every turn.
Here’s the pattern in action:
First, he downplays the number of measles cases in the U.S., implying the disease isn’t serious or widespread, a classic tactic to erode the perceived value of vaccines. But measles isn’t benign, and outbreaks return quickly when vaccination rates drop.
Next, he pivoted: “Vitamin A is important for measles.”
While Vitamin A may reduce complications after infection in vitamin-deficient countries, it doesn’t prevent measles or eliminate the need for vaccination. It's a red herring, a distraction dressed as a solution, once again shifting away from the benefits of vaccines: prevention.Then, he claimed “we don’t know what’s in vaccines”, creating the illusion of secrecy to make inaction feel cautious, when it’s actually risky in the face of infectious disease.
Then came the moral panic: alleging that vaccines contain “aborted fetus debris.” In reality, vaccines are made using well-characterized fetal cell lines developed decades ago. The final products are purified, with no fetal tissue present. This is just fear-mongering wrapped in moral outrage.
Next, he insinuated that vaccines don’t contain real saline placebos, a tactic meant to discredit clinical trials. Vaccines, hace in fact, been tested against saline placebos.
Then he moved the goalposts again: “We just need better treatments.”
But that’s like waiting for a parachute after the plane is on fire. Prevention and treatment aren’t interchangeable — both matter, but one doesn’t excuse the absence of the other.And of course, he falls back on the long-debunked trope: “We need more studies on vaccines and autism.” Despite dozens of large-scale studies, hundreds of thousands of participants, and a clear consensus that no causal link exists, he is instructing a vaccine-denier, David Geier, to conduct a study.
This is not healthy skepticism or scientific inquiry in ANY capacity.
It’s a deliberate strategy of distraction and distortion:
Downplay the disease
Distract with treatments (like vitamin A for measles in the US)
Question the ingredients
Discredit the trials
Invoke moral outrage
Demand perfection
Ignore the evidence
Move the goalposts
Repeat
By constantly reframing the conversation, RFK Jr. isn’t offering informed critique, he’s weaponizing uncertainty and the false balance that is tethered to it.
We don’t treat airplane safety by removing GPS.
We don’t test parachutes by jumping without one.
And we don’t fight infectious diseases by pretending the answers don’t already exist.
Public health isn't built on perfection, it's built on progress, iteration, and evidence. Vaccines, like aircraft or engineering systems, evolve by building on what we know works. RFK Jr.’s narrative thrives on erasing that context and isolating risks, distorting facts, and shifting the goalposts to keep trust perpetually out of reach.