Autism prevalence is up but scientists have consistently found that vaccines don’t cause it

A post on Facebook has claimed that the autism rate in US children has increased along with the number of vaccines they receive.

“1983: US Children 10 vaccines

Autism rate: 1 in 10,000

2008: US children 36 vaccines

Autism rate: 1 in 150

2013: US children 46 vaccines

Autism rate: 1 in 88

David Icke, Facebook page, 9 July 2019

Most of the numbers in the graphic are wrong. Although the estimated rate of autism has been increasing since the 1980s in the USA (and UK) and the number of recommended vaccines has also increased, it’s consistently been shown that there is no link between vaccines and autism.

Vaccines do not cause autism

Multiple academic studies have proven that there is no link between autism and vaccines. One particularly large study looked at over one million children and found no link between autism disorders and vaccines. A large number of studies have shown there is no link between the MMR vaccine (the vaccine which this type of claim is most often made about) and autism.

The children’s vaccination schedule in the US doesn’t recommend as many vaccines as the image says

In 1983, it was recommended that children (aged 0-18) in the US got four vaccinations, not ten as the image says. Getting these four vaccines involved about 11 doses in total between birth and age 18.

In 2008, the standard US children’s immunisation schedule for children included around 13 vaccines. Counting individual doses of all the recommended vaccines including flu (which doesn’t have good uptake), it comes to 39 doses. Without flu it comes to 34.

In 2013, the schedule also recommended US children get 13 vaccines. If you count the total number of individual doses, it comes to about 53 counting individual doses of the recommended flu vaccines. Without flu it comes to 35 doses.

In 2008 flu jabs were recommended annually until the age of five, and in 2013 were recommended annually until the age of 18. We counted the number of doses with and without flu jabs here as the vaccine’s coverage for children in the US was between 40% and 60% between 2009 and 2013.)

We’ve not included vaccines only recommended for high risk groups in our figures.

The number of US diagnoses of autism disorders have increased, although the figures in the picture aren’t all correct

The Center for Disease Control and Prevention (CDC) says it has only been officially monitoring the prevalence of autism disorders in the US since 1996. We don’t have official or comparable statistics for before then, but a number of studies have been published on the subject.

Several organisations report that the prevalence of autism was 1 in 10,000 in the 1980s. One study looked at children born in Denmark in 1983, and two others looked at children born in the early 1960s, in Japan and in Sweden. Others put it higher in the US—we’ve found scientific papers that say the prevalence of diagnosed autism was 1 in 2,500 in the “early 1970s”, or prior to 1985.

Inconsistencies in reported data may come from confusion over whether the prevalence is counted by the year of the study, or the year of birth of subjects in the study. Many papers look at prevalence of autism in eight year-olds.

The CDC estimated in 2008 that one in 88 children in the US had an autism spectrum disorder (based on samples of children aged eight). We can’t find a figure for 2013, but for 2012 it was estimated at 1 in 69 and in 2014, 1 in 59. Confusion may have stemmed from the fact that the one in 88 figure from the 2008 study was reported in 2012.

Scientists don’t know what exactly causes autism, but generally agree that it’s a combination of environmental and genetic factors. Diagnosis has to be done by clinicians on the basis of behaviour, and now that usually happens by the age of four. The CDC says prevalence varies widely by location.

Why have the number of diagnoses increased?

It’s true that the number of diagnoses of autism spectrum disorders are increasing in the US. A similar increase has been seen in general, globally. Data on the UK is limited, but it looks like diagnoses of autism in children increased in the 1990s and early 2000s, before levelling out between 2004 and 2010. Other studies found it has probably stayed level in adults between 2007 and 2014.

The CDC says “It is unclear how much of this increase is due to a broader definition of ASD and better efforts in diagnosis” and that “a true increase in the number of people with an ASD cannot be ruled out.”

Some studies have argued that expanding the criteria for autism diagnosis and improved awareness of autism have led to higher rates.

In 2018, the CDC said that conclusions about the change in prevalence estimates over time should “be made with caution”.

It said: “although study methods and geographic areas of coverage have remained generally consistent over time, temporal comparisons are subject to multiple sources of bias and should not be misinterpreted as representing precise measures that control for all sources of bias.”