A study just came out of Sweden that’s been making headlines, and the headlines aren’t wrong exactly, but they’re easy to misread. So let’s slow down and actually walk through what the researchers found, what it means, and just as importantly, what it doesn’t mean.
What the study actually looked at
Researchers at Karolinska Institutet in Stockholm tracked an enormous group, nearly 3.7 million people born in Sweden between 1987 and 2021, using the country’s health and education records. The study was published in JAMA Pediatrics on September 21, 2026.
Out of that huge group, 975 people had been diagnosed with a congenital TORCH infection. TORCH stands for a specific group of infections that can sometimes pass from a pregnant woman to her developing baby: toxoplasmosis, other infections like syphilis, rubella, cytomegalovirus, and herpes simplex virus. These infections can occasionally cross the placenta during pregnancy, and when they do, they can affect how a baby’s brain develops.
The researchers followed everyone in the study for up to 30 years, which is what makes this study genuinely valuable. Most research on this topic hasn’t had the time or the sample size to track outcomes this far into people’s lives.
What they found
Children born with a congenital TORCH infection were about three times more likely to later be diagnosed with autism than children without one. The risk of intellectual disability was even higher, more than seven times greater, and for the most severe cases of intellectual disability specifically, the risk climbed as high as thirty times.
At an individual level, the researchers estimated that roughly one in five children born with a TORCH infection went on to develop autism.
The study also found something worth noting even among children who weren’t diagnosed with autism or intellectual disability at all: kids with a congenital TORCH infection tended to have lower average school grades than kids without one. That suggests these infections might have a broader effect on development, even in cases that never reach a formal diagnosis.
Interestingly, the researchers didn’t find a similar link between TORCH infections and other conditions like ADHD or obsessive-compulsive disorder. That specificity is useful information in itself, since it suggests the effect isn’t just a general “any infection raises risk of anything” pattern.
Why the researchers are confident this isn’t just coincidence
One of the stronger parts of this study is how the researchers tried to rule out other explanations. They compared children who had a TORCH infection to their own siblings who didn’t, which helps control for shared family factors like genetics or home environment. The association between TORCH infection and autism held up even in that comparison, which makes it harder to explain away as just a family or genetic pattern that had nothing to do with the infection itself.
Reneé Gardner, a researcher at Karolinska Institutet’s Department of Global Public Health who worked on the study, put the bigger picture well: these infections account for a very small share of autism cases across the whole population, but for the specific children affected by one, the increase in risk is real and significant.
Here’s the part that matters most: relative risk versus actual numbers
This is where a lot of news coverage of studies like this gets misleading, not because the numbers are wrong, but because “three times the risk” sounds a lot scarier out of context than it actually is at the population level.
Congenital TORCH infections are rare. Out of 3.7 million people in this study, only 975 had one, a tiny fraction of the total. The researchers estimated that these infections account for only about 1.2% of severe intellectual disability cases in Sweden, and roughly 0.034% of autism cases overall. In other words, even though the relative risk increase for an affected child is large, TORCH infections explain only a very small slice of autism cases across the general population.
If you’re pregnant or planning to be, this study isn’t telling you that autism risk in general just tripled. It’s telling you that this one specific, uncommon complication carries a meaningfully higher risk for the small number of babies affected by it.
A quick, important clarification about vaccines
Some coverage of this study has mentioned that certain TORCH infections, rubella in particular, can be prevented through vaccination. It’s worth being very clear about what that does and doesn’t mean, especially since autism and vaccines have such a loaded history online.
The rubella vaccine prevents rubella infection. Preventing a rubella infection during pregnancy prevents one of the possible TORCH infections this study looked at, which in turn may lower one specific, rare risk factor. That is a completely different claim from the long-debunked idea that vaccines themselves cause autism, a claim based on a single fraudulent, retracted 1998 study that has been thoroughly disproven by decades of research since. This new study says the opposite of that old myth: getting vaccinated against rubella removes a risk factor associated with autism, rather than creating one.
What this actually means if you’re pregnant or planning to be
This study isn’t a reason to panic, and it isn’t really actionable in the sense of something new you need to start doing tomorrow. Most of what helps here is already standard prenatal care: routine screening for infections during pregnancy, staying current on recommended vaccinations like rubella before conception when possible, and basic precautions around toxoplasmosis exposure, like being careful with raw meat and cat litter, which your provider has likely already mentioned.
If you’re currently pregnant and have questions about TORCH infections specifically, that’s a conversation for your OB-GYN or midwife, not something to try to self-manage based on a news study. They can tell you what’s actually relevant to your specific pregnancy and health history.
The bottom line
This is a well-designed study, large, long-running, and careful about testing whether the link could be explained by something else. It adds real evidence that certain rare prenatal infections can meaningfully affect brain development. But it’s also a study about something uncommon that explains a small fraction of autism cases overall, not a new general risk factor that applies to most pregnancies. Both things are true at once, and that nuance tends to get lost in a headline built for three seconds of attention.
Frequently Asked Questions
What are TORCH infections?
TORCH is a group of infections that can pass from a pregnant person to a developing baby: toxoplasmosis, other infections like syphilis, rubella, cytomegalovirus, and herpes simplex virus.
Does this study prove TORCH infections cause autism?
It shows a strong statistical association, including in comparisons between siblings, which strengthens the case. But it’s an observational study, so it demonstrates a link rather than definitively proving direct causation in every case.
How common are congenital TORCH infections?
Very rare. In this study of 3.7 million people, fewer than 1,000 had a diagnosed congenital TORCH infection.
Does this mean vaccines prevent autism?
Not exactly. It means the rubella vaccine prevents rubella infection, which is one of the rare TORCH infections linked to higher autism risk in this study. That’s different from claiming vaccines directly prevent autism in general, and it has nothing to do with the debunked, retracted claim that vaccines cause autism.
Should pregnant women be tested for TORCH infections?
That’s a decision to make with your own healthcare provider, since testing recommendations depend on individual risk factors, symptoms, and regional guidelines, not something a single study changes on its own.