No plausible explanation given for the lack of symmetry in "rapid onset" autism cases

Thousands of parents have noticed (and posted) that their child was developing normally until a vaccine changed that in a matter of days. It only happens after a vaccine shot, never before AFAIK.

Executive summary

The McDowell triplets were developing normally and then, within hours after a vaccine shot, became severely autistic.

There are thousands of similar stories from parents all over the world of their child developing normally and then, hours to days after a vaccine, the child all of a sudden transitioned into exhibiting classic ASD behaviors, generally for the rest of their lives.

Former pediatrician Doug Hulstedt had 44 rapid onset autism cases in his practice. When he looked back at the timing, he discovered that all 44 happened within 1 week after a vaccine appointment, never before.

Beth Lambert has been studying autism for over 20 years. In those 20 years, she’s heard of hundreds of rapid onset autism cases. In every single case she is aware of, the rapid onset autism happened shortly after one of three types of events: vaccination, anesthesia, viral infection. The stats from pediatrician Liz Mumper are similar. In her more than 200 cases, 90% of these cases happened right after a vaccine (often with Tylenol and infection as co-factors).

Stories of rapid onset autism happening in the week BEFORE a vaccine appointment appear to be rare to non-existent:

Grok says this is because parents who noticed this have no reason to post their stories. But I pointed out that there are plenty of pro-vax parents who would like nothing more than to show that the anti-vaxxers are wrong. If any such a story existed, even if it was just a single one, I would be hammered with that story any time I posted on the topic of whether vaccines can trigger autism.

I asked Grok to explain the asymmetry.

Grok gave nearly exactly the same response it gave before, claiming that those experiencing rapid onset autism before a vaccine appointment have no “narrative hook” to post their story even after I pointed out the hook exists for both sides.

There are 15,000 pediatric practices in the US. Nearly every single one is run by pro-vax doctors. These practices would be expected to have the data on when the PARENTS first noticed rapid onset autism in their medical records.

If autism is not related to vaccination, we’d expect to aggregate the data and find that the rapid onset autism rates happened with equal rates before vs. after the vaccine appointment.

But as far as I can tell, there are no such pediatric practices with more rapid onset cases before the vaccine vs. after the vaccine. Most don’t want to look and when you ask them to look, they will refuse to look.

When researchers study these cases, they never request exact date of onset or the onset date relative to the nearest vaccination date.

Pediatrician Elizabeth Mumper has seen over 200 regressive autism cases (rapid onset)

ESTIMATE from Dr. Mumper:

One third to 50% regressive in 48 hrs

OF those:

• 90% after vaccines, usually with acetaminophen as co-factor, often when multiple vax given while sick or MMR

• 7% after viral infections

• 3% after anesthesia/surgery especially those with mitochondrial dysfunction or detox impairments

Her stats are very similar to stats from other practioners like Michael Goldberg, MD.

The statistics for twins is even more compelling. Hundreds of cases, but nearly all of them happened after a vaccine. None of the in the peer reviewed literature!

There are hundreds of cases of twins with rapid onset autism within hours of each other. Every single time, there was a medical trigger. In most cases, it was a vaccine.

From Grok:

If it was random, parents would be blaming anything that happened in the previous 48 hours. But they all seem to point the finger to the same thing. The chance that this is simply random is tiny.

My call for a counter example gave no results

Steve Kirsch@stkirsch

Every single case of twins getting autism within hours of each other was precipitated by a medical trigger which, in most all cases, was a vaccine. If you have a counter-example, post it here. I'll wait.

8:42 PM · Mar 16, 2026 · 7.55K Views

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11 Replies · 129 Reposts · 469 Likes

Claude finds the fact that the medical community doesn’t want to do the study looking at the relative dates very troubling

Claude finds all of this very troubling (see my Claude conversation).

Claude finds the asymmetry compelling and is deeply troubled by the medical community refusing to look at the timing data and pre-maturely declaring that the science is settled.

The Taylor (1999) study didn’t ask for the date of onset

The Taylor study found a higher incidence in autism reports 6 months after vaccination, but wrote it off as an “artifact.” Of course! Why didn’t I realize that! That explains it perfectly, doesn’t it? It was an artifact of imprecision.

From the paper:

“No significant temporal clustering for age at onset of parental concern was seen for cases of core autism or atypical autism with the exception of a single interval within 6 months of MMR vaccination. This appeared to be an artifact related to the difficulty of defining precisely the onset of symptoms in this disorder.”

The study was deliberately structured to avoid finding a signal. They didn’t ask for the DATE of onset, but simply asked for the child’s age (e.g., 18 months). They did determine DATEs of vaccination. So there is no possible way for them to determine if the autism happened before or after the shots. The deliberately construct these studies to find no signal and make fun of you if you question them on this practice.

They construct the studies so no signal can be detected

Grok confirms that there is no study where they used dates

Parents have the data, but researchers don’t ask

The parents, in THOUSANDS OF CASES, have the exact relative dates between the nearest vaccine and autism. We know that because they post their experiences on X with precise recall. But scientists never request the dates so they can do the study.

AFAIK, no pediatric practice has higher numbers before the shot than after the shot

The honest scientific studies all find similar odds ratios (OR) associating vaccines and autism

See this article by Toby Rogers which lists the studies and the odds ratio in each study.

An OR of 4 translates into 75% or more of the autism is caused by vaccines (population attributable risk calculation which is PAR=(OR-1)/OR.

$1,000 reward if you can show me even ONE counterexample!

I’m willing to put my money where my mouth is.

Comments on my post

AAP should provide the statistics from their members to prove I’m wrong

I shouldn’t need to do this. AAP should just survey their members and prove me wrong. They could do this with a single email to their members. We’d know instantly. Just ask the members to report two numbers: week before # and week after #.

Will they do this? I don’t think so.

The fact that they aren’t proactively jumping on this to prove they are right is troubling, isn’t it? A single email could settle this important issue and prove they are right.

I emailed their media relations for a response and will update this article if I receive a reply.

Summary

You can’t have tens of thousands of kids becoming rapidly autistic within 1 week after a vaccine appointment vs 0 kids regressing in the week before the appointment if there is no causality.

This is not a reporting artifact.

As far as I know, there is no pediatric practice in the world where the statistics are anything but severely lopsided for rapid onset autism.

If autism were not caused by vaccines, the “coincidence” would happen 4% of the time, not 90% of the time.

And not a single mainstream autism expert will acknowledge the obvious asymmetry because none of them want to destroy their career. So they stay silent and keep recommending the shots.