Congenital toxoplasmosis, syphilis, rubella, cytomegalovirus, or herpes simplex (TORCH) infections are rare but are associated with intellectual disability and autism, as shown in a study.
In a Swedish population-based cohort of more than 3 million individuals (mean age at follow-up 19 years), individuals exposed to TORCH infections had higher rates of autism (5.39 vs 1.71 diagnoses per 1,000 person-years) and intellectual disability (8.22 vs 0.68 diagnoses per 1,000 person-years), reported first author Hugo Sjöqvist, a PhD student at Karolinska Institutet, Stockholm, Sweden, and colleagues. [JAMA Pediatr 2026;doi:10.1001/jamapediatrics.2026.4229]
Having a TORCH infection was associated with elevated risks of autism (hazard ratio [HR], 3.10, 95 percent confidence interval [CI], 2.55–3.76) and intellectual disability (HR, 7.22, 95 percent CI, 6.14–8.49). These associations were replicated in sibling analyses, with similar risk estimate for autism (HR, 3.19, 95 percent CI, 1.97–5.15) and a higher estimate for intellectual disability (HR, 11.28, 95 percent CI, 5.97–21.33).
“We also observed that individuals exposed to TORCH infections had lower academic performance in adolescence, even in the absence of diagnosed autism or intellectual disability,” Sjöqvist and colleagues said.
“Together, these findings suggest that TORCH exposures may be associated with lasting cognitive performance outcomes into adolescence, even in the absence of diagnosed neurodevelopmental conditions,” they added.
Congenital TORCH infections are caused by vertically transmitted pathogens that have been associated with adverse foetal and neonatal outcomes. These pathogens can cross the placenta and infect the developing foetus, increasing the risks of miscarriage, stillbirth, and pregnancy complications. [Clin Perinatol 2015;42:77-103; Nat Rev Microbiol 2022;20:67-82]
“Characterizing the full spectrum of consequences of symptomatic and asymptomatic congenital TORCH infections should be a research priority,” Sjöqvist and colleagues said, “and preventive strategies, particularly for cytomegalovirus and in settings with higher rates, should be strengthened.”
The analysis included 3,666,002 individuals born in Sweden. Of these, 975 had congenital TORCH infections (mean age at follow-up 18.7 years, 54.6 percent male) and 3,665,027 had no exposure to TORCH (mean age at follow-up 20.5 years, 51.4 percent male).
Congenital TORCH infections were more likely to occur with obstetric complications, including cesarean delivery (14.9 percent vs 7.3 percent), low Apgar score (<7: 7.9 percent vs 1.1 percent), preterm birth (31.5 percent vs 5.8 percent), and small for gestational age (13.4 percent vs 2.3 percent).
Congenital TORCH infections showed no association with either attention-deficit/hyperactive disorder or obsessive compulsion disorder.