Can Infections Cause Autism? What the Latest Science Says

If you're a parent, caregiver, or loved one of someone on the autism spectrum, you've likely found yourself deep in research rabbit holes looking for answers to questions like: What causes autism in children? Why does one child develop with a neurotypical brain while another shows early signs of neurodevelopmental delays?

These questions are tough, especially because the internet is full of conflicting theories and misinformation. Fortunately, science is catching up to the conversation and shining a light on important clues. Among the many areas being studied, one connection is gaining increasing attention: the link between infections and autism.

Chronic infections and the immune system’s overreaction to them may play a surprising role in how autism develops. Let’s take a closer look at what current research reveals about infections, genetics, and how they may influence autism development.

WHAT CAUSES AUTISM IN CHILDREN?

Autism spectrum disorder (ASD) is a complex, multifactorial condition that affects communication, behavior, and social interaction. But what causes autism in children isn't as simple as one root trigger. It’s the result of a web of factors including genetics, environmental exposures, immune responses, and possibly even prenatal infections.

Research shows that many autistic people show a combination of neurological inflammation, immune dysregulation, and gut-brain axis disruption. In some cases, these issues seem to arise after a series of infections or immune challenges.

This aligns with growing research suggesting a link between maternal infections and autism risk. In fact, a 2018 study reported that mothers who had infections during pregnancy, especially severe ones requiring hospitalization, had a higher risk of giving birth to a child later diagnosed with autism.

This supports the idea that prenatal infections and autism risk may be more deeply connected than once believed.

CAN INFECTIONS CAUSE AUTISM?

It’s a sensitive and often controversial question: can infections cause autism? While infections alone are not typically the sole cause, they may act as a trigger in some children with genetic or neurological vulnerabilities.

The team at Amen Clinics has studied nearly 300,000 brain scans and found patterns of inflammation and abnormal activity in children with ASD, suggesting a possible immune-related cause. Infections such as chronic viruses, bacteria, mold, and yeast can actually inflame the brain and disrupt normal developmental processes.

Emerging studies further support this as one research review published in Frontiers in Psychiatry confirmed that early-life infections and maternal immune responses are significantly associated with neurodevelopmental outcomes, including autism.

This doesn't mean all infections will lead to autism. Instead, for some children, particularly during key developmental windows, they may increase vulnerability.

Understanding the link between infections and autism is not about assigning blame, especially not toward mothers or caregivers. Rather, it’s about uncovering pieces of the puzzle that may lead to more effective treatments and early interventions for autism.

HOW DO INFECTIONS AFFECT AUTISM DEVELOPMENT?

Infections aren’t always obvious or short-lived; they can sneak up on you. Chronic, underlying infections can linger in the body and create an inflammatory environment that affects the brain and nervous system.

Here’s how specific infections are linked to autism symptoms and what to look out for:

PANS and PANDAS: The Sudden Shift

PANS (Pediatric Acute-onset Neuropsychiatric Syndrome) and PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections) are conditions where a simple infection triggers an autoimmune response that targets the brain.

In some children, this can lead to sudden-onset OCD, tics, and changes in behavior, moods, sensory perception, and motor function. Some of these changes can mimic or intensify autism traits.

In fact, many children’s symptoms dramatically shift after an infection, highlighting how vulnerable the developing brain can be to immune assaults.

Lyme Disease: The Silent Saboteur

Lyme disease, caused by the Borrelia burgdorferi bacterium, can infiltrate the brain and nervous system, leading to cognitive decline, mood disturbances, and behavior changes. In some children with ASD, undiagnosed Lyme disease can exacerbate symptoms of autism or be a contributing factor in regression.

Testing and targeted antibiotic or herbal treatments have helped some patients recover key functions over time.

Mold Exposure: More Than an Allergy

Indoor mold isn't just a household nuisance. It’s a neurotoxic threat. Mold releases mycotoxins, which can provoke immune responses and neuroinflammation. Children with autism often have detoxification pathway issues, making them more sensitive to environmental toxins like mold.

Mold remediation and detox support have led to significant symptom improvements in some cases.

Yeast Overgrowth and Gut-Brain Health

The gut-brain connection is a crucial part to understanding autism, so anything that affects that needs attention. Yeast overgrowth—particularly Candida albicans—can alter neurotransmitter production, immune function, and behavior.

Stool testing can help identify yeast imbalances. Treatments such as anti-fungal treatments, probiotics, and dietary changes may help restore balance. The result? Improved language, mood, and focus in some children.

All of these infections illustrate how complex and interconnected the link between infections and autism truly is. They're not just background noise and are often active contributors.

HOW DOES GENETICS AFFECT AUTISM DEVELOPMENT?

While infections play a role, genetics are still believed to be a significant part of the autism picture. Research shows that some children are genetically more susceptible to immune system overreactions or have mutations that affect brain development, detoxification, and nutrient absorption.

WHAT YOU CAN DO: ADDRESSING THE LINK BETWEEN INFECTIONS AND AUTISM

Now that we’ve explored how infections and autism intersect, what can you do if you're a parent or caregiver?

1. Start by working with a knowledgeable mental health professional who understands both the brain and the immune system.
2. Seek out comprehensive testing for infections, toxins, and genetic vulnerabilities.
3. Advocate for stool analysis, mold testing, and other screening tests.
4. Build a support team that you can trust with science-backed resources.

When infections, inflammation, and nutritional deficiencies are addressed early, many people see improvements in autism symptoms.

FINDING A NEW WAY FORWARD FOR AUTISM

Understanding the link between infections and autism gives you better direction to find the best solutions for your child with autism or for another loved one who has the condition.

If you’re ready to learn more, register for Amen University’s Autism: A New Way Forward. With insights from renowned psychiatrist and brain health expert, Dr. Daniel Amen and pediatrician and autism recovery specialist Dr. Jerry Kartzinel, this digital autism course can help guide you through a more personalized, brain-based approach to autism care.