The 'Fever Effect' May Unlock New Autism Treatment

Many parents of autistic children report their child's symptoms fade when they have a fever. Now, scientists are studying the phenomenon to determine whether the "fever effect" could be a treatment option.

Autism spectrum disorder (ASD) causes a wide range of social, behavioral, and language-related symptoms. While debate exists among autistic individuals and health experts about whether autism is a disorder or difference, most would agree that easing the severity of symptoms can help improve daily life for autistic people.

Interestingly, some parents and health experts believe that having a fever, characterized by a body temperature of 100.4 °F or higher, appears to help reduce social and behavioral symptoms in some autistic individuals.

In a 2017 study involving 2,152 autistic children, 17% experienced improvements in communication, behaviors, and social interaction when they had a fever. The scientists found that this "fever effect" was more likely to occur in children with significantly lower non-verbal cognitive skills, language levels, and more repetitive behaviors.

However, other research conducted in 2022 suggests that fevers have the opposite effect on children with ASD, revealing that only three out of 141 autistic participants experienced a reduction in their symptoms during a fever.

Nonetheless, some parents firmly believe that fevers positively impact their autistic child's behavior.

Could the fever effect lead to new autism treatments?

To understand the fever effect, scientists from MIT and Harvard Medical School, through grants from The Marcus Foundation, plan to study it in the hope of developing a new treatment option for autism.

"Although it isn't actually triggered by the fever, per se, the 'fever effect' is real, and it provides us with an opportunity to develop therapies to mitigate symptoms of autism spectrum disorders," said Gloria Choi, associate professor in The Picower Institute for Learning and Memory and the Department of Brain and Cognitive Sciences at MIT, in a press release.

The team's previous research found evidence that an immune signaling molecule called IL-17a may be a mechanism behind the fever effect.

When the scientists tested this finding on mice by administering IL-17a directly to the brains of rodents with autism-like symptoms, those symptoms improved.

Now, the researchers want to determine if mimicking the fever effect by giving extra IL-17a could benefit autistic individuals.

The team will use mice to identify how IL-17a and similar molecules might improve social abilities and lessen repetitive behaviors. Then, they plan to obtain blood and other biological samples from human participants with and without ASD to determine clinical and biological markers linked to the fever effect.

If the investigation reveals these markers, the scientists believe they could use that information to develop therapies that produce the benefits of the fever effect without the need to induce a fever.