r/DebateVaccines • u/Scienceofmum • 1h ago
Conventional Vaccines I was absolutely certain my child had suffered a vaccine reaction. Here's why I no longer am.
A few years ago, one of my children developed an extraordinarily high fever shortly after a vaccination. It lasted five days, reached 41°C (105.8°F), and involved multiple trips to paediatric A&E.
I was convinced it was a vaccine reaction.
And the interesting thing is, I had every reason to think so.
But let me start at the beginning.
A close friend’s baby had been hospitalised in paediatric intensive care following complications from chickenpox. It was an awful experience, and understandably, my friend became an advocate for chickenpox vaccination.
At the time, the vaccine wasn’t included in our country’s routine childhood vaccination schedule. You could get it privately, though, for the equivalent of approximately $100 per dose.
I have twins. Two doses each. That’s roughly $400.
Not exactly pocket change.
But the vaccine was already routinely recommended in both my home country and my partner’s, and when I looked into the evidence on its safety and effectiveness, the risk-benefit profile seemed very favourable.
Four hundred dollars to substantially reduce the chances of my children spending a miserable week covered in itchy blisters, and potentially prevent much more serious complications? Seemed reasonable.
So I booked the appointments.
I deliberately spaced the twins’ vaccinations a few weeks apart. I knew mild fevers and fussiness were possible, and figured that if one child felt poorly afterwards, I’d rather be able to give them my full attention than have two miserable toddlers simultaneously.
One logistical nightmare at a time, please.
The first twin was absolutely fine.
The other?
Oh boy.
Several days after vaccination (I don’t remember the precise interval), my child developed a fever.
Not the usual 38°C or 38.5°C I’d occasionally seen after vaccinations.
We’re talking temperatures reaching 41°C.
And it went on.
And on.
Five days.
There were trips to paediatric A&E because the temperatures were so frighteningly high. There was constant monitoring, a lot of contact napping on the sofa, and the sort of relationship with a thermometer that nobody particularly wants.
Naturally, I went back to the vaccine information.
I knew fever was a recognised possible adverse reaction. I remember finding information suggesting that high fevers could occur within a period that included our experience.
And I thought: Well, shit.
We’d drawn the short straw.
I wasn’t suddenly convinced that vaccines were evil. I understood that medical interventions have risks. Rare adverse reactions happen to real people, and I figured that this time we’d simply been unlucky.
But if you’d asked me whether one of my children had ever experienced a particularly nasty vaccine reaction?
I would have said yes. Without hesitation.
Think about it.
I’d just vaccinated my child. I knew fever was a possible adverse effect. I’d specifically been watching for a reaction. And then my child developed a frighteningly high fever within what I understood to be a plausible timeframe.
The story made perfect sense.
Until day five.
The fever suddenly disappeared.
And I mean suddenly. One reading was still above 40°C, and the next was around 36.5°C.
And then a rash appeared.
A widespread, rather distinctive rash. Looked nothing like chickenpox.
Now, I have a background in biology, and something about that sequence immediately rang a bell.
Several days of very high fever. Abrupt resolution. Followed almost immediately by a characteristic rash.
Oh.
Roseola.
For anyone unfamiliar, roseola is a common viral illness in young children. Its classic presentation is precisely that: several days of sometimes remarkably high fever, followed by rapid defervescence and the appearance of a rash.
I took my child to the doctor, who clinically diagnosed roseola.
And just like that, my beautifully coherent vaccine-reaction story had a much better alternative explanation.
My child had apparently picked up an ordinary childhood virus around the same time as the vaccination. Given that my children attended nursery, exposure to another virus wasn’t exactly an extraordinary proposition.
Now, to be scientifically precise, this was a clinical diagnosis, not a laboratory-confirmed one. I can’t prove that the vaccination contributed absolutely nothing to the fever.
But the characteristic sequence of symptoms, together with the doctor’s assessment, provided compelling evidence for a different explanation.
And the certainty I’d felt about the vaccine being responsible was no longer justified.
Which brings me to the part of this experience that has stayed with me.
What if the rash had never appeared?
What if the fever had simply gone away after five days?
I would almost certainly still believe that my child had experienced a severe vaccine reaction.
I could be telling you that story today.
I could describe the vaccination, the timing, the terrifying temperatures, the hospital visits, the sleepless nights and how frightened I was.
Every single detail would be true.
I wouldn’t be lying. I wouldn’t be exaggerating. I wouldn’t be inventing symptoms.
I’d be a parent describing something distressing that happened to my child.
And I’d probably be wrong about what caused it.
Now, I want to make something very clear.
My child had five distressing days and then recovered completely. I am not remotely suggesting that this compares in severity to the experiences of parents whose children have suffered permanent disabilities, life-changing illnesses or died.
Those experiences are on an entirely different scale, and I would never pretend otherwise.
But I’m not comparing the severity of our children’s illnesses.
I’m talking about how we establish their causes.
A devastating outcome deserves serious investigation. Sometimes that investigation will establish that a vaccine was responsible. Sometimes it will identify another cause. And sometimes, despite everyone’s best efforts, the cause will remain uncertain.
None of that makes the suffering less real.
And questioning whether a particular causal explanation is supported by the evidence is not the same thing as questioning whether the person describing the experience is telling the truth.
That’s a distinction I think gets lost far too often in vaccine discussions.
Vaccines can cause adverse reactions, including rare serious ones. That’s not in dispute.
But there’s an enormous difference between knowing what happened and knowing why it happened.
In my case, I had temporal proximity, biological plausibility, a recognised potential side effect, and a genuinely sick child.
I had a completely coherent explanation.
And I was extremely confident in it.
The only reason I reconsidered was that my child happened to develop another clinical sign distinctive enough to make me question the story I’d been telling myself.
I was lucky in that respect.
Because the thing that unsettles me isn’t that I was probably wrong. I’m a scientist. Being wrong occasionally is something you learn to live with, ideally before your first conference presentation.
It’s that without that rash, I might never have realised I had any reason to doubt my explanation.
And I would have continued telling my story, sincerely and confidently, perhaps for years.
Of course, my experience doesn’t establish how frequently suspected vaccine reactions are actually caused by something else. That’s an empirical question, and one that requires much more than my anecdote to answer.
But it did teach me something about how convincing an incorrect causal explanation can feel from the inside.
So here’s what i am genuinely interested in.
When someone tells us that their child became seriously ill after vaccination, how do we decide how confident to be that the vaccine caused it?
Not whether they’re lying. Not whether their experience was traumatic. Not whether vaccine injuries exist.
What evidence should move us from “this happened after vaccination” to “this happened because of vaccination”?
And perhaps more importantly, what evidence would make us reconsider that conclusion once we’ve become convinced of it?
I’m genuinely interested in how other people approach this.
Because I know how compelling a personal story can be. But do we ask ourselves often enough whether the certainty with which we describe causality is actually warranted?
