World Autism Awareness Day: Vaccines did not cause Rachel’s autism

World Autism Awareness Day, marked annually on 2 April, seeks to raise awareness for the millions of people worldwide who live on the autism spectrum.

I have a unique connection to this day because my youngest daughter, Rachel, is 26 years old and has autism in addition to a number of intellectual disabilities. Because I’m also a vaccine scientist and pediatrician (who develops neglected tropical disease vaccines), I often find myself defending vaccines against a rising antivaccine movement in both America and Europe.

Autism affects one in 200 people

This movement alleges that vaccines somehow cause autism, and in response I’ve written a new book with the self-explanatory title, Vaccines Did Not Cause Rachel’s Autism (Johns Hopkins University Press). 

We can begin a discussion about autism in a number of ways, but because our RSTMH is first and foremost a global health organisation it is interesting to take that perspective. According to the Institute of Health Metrics and Evaluation’s Global Burden of Disease Study (GBD) 2017, there are approximately 32 million people living on the autism spectrum, or roughly one in 200 individuals.

Autism under-diagnosed in girls and women

However, that number is almost certainly an under estimate, especially since we are getting much better at diagnosing girls and women with autism.

Increasingly, we recognise that, like Rachel, girls and women are often better at camouflaging their autism by being more verbal or interactive, but they also often suffer from high rates of co-morbidities such as obsessive-compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), and even some eating disorders, among other conditions. We can therefore expect the numbers of individuals diagnosed as living with autism to rise precipitously in the coming years.  

Geography of autism

Yet another interesting aspect is the geography of autism. Many people are surprised to learn that children with autism disproportionately live in the world’s low- and middle-income countries (LMICs) of Africa and South Asia, while the highest childhood autism rates are found in the Middle East and North Africa (MENA) and Central Asia. These are data from the GBD 2016.

We therefore face the difficult problem that many children with autism live in countries or areas that are mostly devoid of adequate resources for autism families.

Revision of the way we think about autism

Our traditional norms of thinking about autism are also undergoing radical revision. Many adults on the autism spectrum rightly object to autism being considered as an illness or even a “disorder”.

There is an emerging neurodiversity movement that appropriately de-emphasises these aspects of autism, with some individuals highlighting the fact that it’s often not the autism per se that disables but instead the intellectual disabilities or other co-morbidities that often accompany autism. This last aspect is especially relevant to the antivaccine lobby that wrongly claims vaccines have caused an autism “epidemic”. 

In my recent book I summarise the strong evidence – based on epidemiologic studies of over one million children – that vaccines do not cause autism. I also explain how vaccines simply cannot cause autism from studies showing that autism is strongly linked to genes involved in early foetal development. 

Antivaccine lobby and misinformation

The point being that autism begins in pregnancy well before children are ever vaccinated. Indeed, a recent study from dozens of investigators has identified at least 99 genes involved in foetal neuronal gene expression and neuronal connectedness, including many genes involved in the neuronal cytosekeleton. Through whole exome sequencing of Rachel (and my wife Ann and I) we’ve also found a new mutation involved in a similar gene.

Despite the overwhelming evidence delinking vaccines from autism, the antivaccine lobby remains strong and currently dominates the internet, e-commerce, and social media. Through a pervasive misinformation campaign, they cause parents to withhold vaccines from their children.

It is also resulting in reversals of public health gains from global vaccination campaigns, especially in Europe and America. My hope is that further education about autism and the lives of people on the autism spectrum (and their families) might begin countering these damaging trends.