The need for secrecy made me uncomfortable. You might not believe what someone else believes, you might find it barely credible that someone else could give credence to so-called research you find laughable, but we live in a free society.
The documentary bases its allegations on research which has since been labelled the greatest medical hoax of all time.
Dr Andrew Wakefield, a gastroenterologist at the Royal Free Hospital in London, sparked international panic in 1998 when he published research in the Lancet purporting to link the MMR vaccine to autism.
I say "purporting" as the research has since been comprehensively rubbished. Dr Wakefield was found guilty of ethical, medical and scientific misconduct, yet the vaccination debate continues.
Let's not forget the anti-vaccination movement is often driven by parents desperate to find a reason for their child not behaving as they expected. It also feeds off a not unreasonable suspicion many have of big drug companies, which have a history of being selective about what information they publish.
So Vaxxed has hit the big screen and people can make their own judgments, but I suspect most have made up their minds already.
The film's debut raises an important issue. Should we be stopped from unscientific thinking? If so, homeopathy could be out the window; there would be a ban on pilgrims visiting Lourdes looking for miraculous cures.
We are all free to pursue our own beliefs regardless of how whacko others might think them. But when the media abandons its duties in accurately reporting these stories then we are in trouble.
The media's role was one of the most significant parts of the MMR scare. General news hacks looking for a way to sensationalise it jumped on board the inadequate research and sent fear through every family home.
In Britain it was exacerbated by then-Prime Minister Tony Blair and his wife, who wouldn't confirm if they had vaccinated their newborn son Leo.
We can't afford to let that kind of widespread misinformation happen again.Mark Sainsbury hosts Morning Talk from 9am-midday on RadioLIVE.