Zero signs of any link between the measles-mumps-rubella (MMR) vaccine and autism.
It all adds up to one of the largest studies to date investigating allegations that vaccines could be responsible for the development of ASD. But big numbers aside, was it worth the bother?
It's been more than 20 years since the discredited British researcher Andrew Wakefield sparked global hysteria with his claim a common inoculation was in some way responsible for impairing neurological development in young children.
Studies have since failed to support the claim over, and over, and over again. By all accounts Wakefield's study should have long become a textbook example of self-correction in science. We should have moved on.
Yet here we are in 2019 with another monumental epidemiological study asking whether we've missed something, whether maybe – just maybe – there's a stone left unturned.
By taking into account known risk factors for autism and modelling them in connection with the MMR vaccination status of more than half a million subjects, a team of researchers from Statens Serum Institut could rule out even the smallest of chances that the vaccine triggers ASD development.
Autism is a rather complicated condition. There are numerous characteristics contributing to a diagnoses, and diverse severities that make it less a single disorder and more of a spectrum of behaviours and functions.
ASD might or might not be on the rise, depending on how you interpret the statistics as an indication of shifts in diagnostic trends or as a sign of something more profound.
Part of the problem is we're only getting to grasp just how many factors might be at work.
There are clearly a variety of genes that make some difference, many of which can be inherited. Environmental factors such as air pollution also seem to nudge developing biochemistry further towards the autism spectrum.
In spite of Wakefield's work being retracted from the journal in which it was published, researchers have continued to probe the increasingly remote possibility that vaccines might still play a role in the disorder's development.
It's not like there is a lingering doubt within the medical community. But as vaccination rates decline across many parts of the globe and anti-vaccination groups promote misinformation across media platforms, science supporting the relative safety of vaccines remains at a premium.
"Social media continues to be a platform to propagate this and other fake news about vaccines, creating concerns among parents," says Kristine Macartney, Director of the Australian National Centre for Immunisation Research and Surveillance.
But is more science really the answer? Macartney wasn't involved with the initial research, but feels in spite of its merits, future studies such as this one come at a cost.
"Looking forward, continuing to evaluate the MMR-autism myth when it has already been thoroughly debunked will come at the expense of not pursuing other important research to better understand and prevent autism."
Hannah Kirk from the Monash Institute of Cognitive and Clinical Neurosciences agrees.
"Although it is fantastic to see another high-quality study refute the myth of an autism and MMR vaccine link, it is disappointing that substantial research efforts, time and funds have to continue to be directed toward disproving something that we already know to be incorrect; rather than investigating more accurate causes of autism," says Kirk.
Not only are we desperate to know more about the neurology of the autism spectrum, there's a great deal of study left to be done on how to better communicate and change public opinion when it comes to vaccinating our families.
Based on what little we do know, bigger and better studies aren't going to persuade hesitant parents into giving their precious ones a jab of MMR.
"Perhaps it is time to finally lay to rest the false information that MMR causes autism and get on with the important goal of eradicating this deadly disease once and for all," says infectious diseases physician Katie Flanagan from the University of Tasmania.
In 2017, an estimated 110,000 people around the world died as a result of measles outbreaks in areas that weren't adequately protected by vaccination.
If there's one number we really need to pay attention to, it's that one.
This research was published in the Annals of Internal Medicine.