What you need to know about vaccines, autism, and the hubbub over ‘Vaxxed’

The anti-vaccine documentary “Vaxxed” will premiere Friday in New York, giving critics a first look at a film that sparked a ferocious backlash in the scientific community.

The film is directed by a discredited British researcher, Andrew Wakefield, known for promoting the debunked notion that vaccines are linked to autism. It had been set to premiere April 24 at the prestigious Tribeca Film Festival.

But amid a storm of outrage, actor and festival cofounder Robert De Niro, yanked it from the schedule. Now, a small California distributor that had originally planned to distribute the film after the Tribeca premiere has hastily arranged Friday’s debut screenings.

Here’s what you should know about the controversy:

Who’s behind this film?

One of the most scorned men in the medical world. Wakefield, who also co-wrote the film, helped launch and sustain an anti-vaccine movement that public health experts estimate is responsible for thousands of preventable deaths.

In 1998, Wakefield published a study in the Lancet that suggested the widely administered vaccine against measles, mumps, and rubella (known as MMR) could cause autism. In the subsequent years, Wakefield’s research methodology came under fire. As did his financial ties to an attorney seeking to collect damages from vaccine makers.

Wakefield’s paper was retracted and eventually found fraudulent. And the UK’s medical regulator revoked his medical license.

Why are the film’s critics so concerned?

You don’t often see scientists trying to intervene in a film festival. But in this case, they said the danger of fanning discredited fears about vaccines was too great not to speak up.

Vaccination rates are high overall for US kids, but they’re troublingly low in some communities, and that’s led to a resurgence of some diseases. The US saw more cases of measles in 2014, for instance, than it had in any year since world health officials declared the disease eliminated in North America, back in 2000.

And immunization rates in the US could soon dip below the threshold needed to maintain what’s called “herd immunity,” which protects the entire population, researchers reported last fall.

The film’s producers and distributors say the movie is not anti-vaccine and that they they’re just trying to promote vaccine safety.

Do we know what’s in the documentary?

The producers haven’t given screening copies to the media, an unusual move in the film industry. But the online trailer makes it pretty clear how the documentary comes down.

There are snippets of mothers talking about distressing behaviors they noticed in their children after vaccination. Emotional footage of a boy with autism banging his head.

And a chart showing of the rising number of documented autism cases in the US. The film projects a doomsday scenario: If that growth continues apace, by 2032, an astounding 1 out of every 2 children in the country will have autism. Public health experts say that’s not at all likely — and new data released Thursday also casts doubt on a doomsday scenario. The percentage of children with autism remained the same between 2010 and 2012, the most recent years of data, according to the new estimate from the Centers for Disease Control and Prevention. Though it’s too early to tell whether the prevalence of autism has plateaued.

Mostly, though, “Vaxxed” appears to focus on promoting a conspiracy theory.

A conspiracy theory, you say?

That’s right. “Vaxxed” promotes the unsubstantiated claim that the CDC covered up crucial data about a purported link between vaccines and autism.

Here’s the backstory: One of the CDC researchers who co-authored a 2004 study that found no link between vaccines and autism harbored concerns about the way the analysis was conducted.

A decade later, he shared his concerns with the anti-vaccine activist Brian Hooker, who along with Wakefield began to promote the idea of a coverup.

As the conspiracy theory grew, the CDC researcher, William Thompson, came forward with a public statement. He said he wanted to make “absolutely clear” that he believes vaccines save lives and that he would never advise a parent not to vaccinate. Yet he said data had been omitted from the study that would have showed an increased risk for autism among African-American boys who received the MMR vaccine before age 3.

Do we know what actually happened?

The CDC researchers looked at more than 2,400 Atlanta-area kids with and without autism and charted when they’d first been vaccinated against measles, mumps, and rubella. They found no meaningful associations.

The researchers also looked at a smaller subset of the group — the children for whom they could access Georgia state birth certificates containing data on potential confounding factors like birth weight and maternal age. They analyzed that group in several ways, including comparing outcomes across racial groups. Again, no meaningful associations.

The researchers did find that slightly more kids with autism were vaccinated between the ages of 2 and 3. But they said that could well be correlation, rather than causation: Toddlers already demonstrating signs of autism might have been more likely to enroll in pre-K special education programs — and therefore may have needed to get immunized earlier than children without those symptoms.

The documentary trailer concludes that the CDC “sliced and diced” its data and committed fraud.

Those are serious accusations. Could it be fraud?

There’s no reason to think so. Let’s go through the many problems with the conspiracy theory.

Nobody has produced evidence that the CDC covered up anything. The CDC makes the raw data from the study available to researchers to analyze, and no credible scientists have raised an alarm.

There’s also no compelling biological explanation why African-American boys would be the only group at increased risk for autism. The smaller the subgroup you’re analyzing, the more likely you are to stumble across false positives.

Hooker, the anti-vaccine activist, did his own analysis of the raw data, looking at all African-American kids, not just those with Georgia birth certificates. He found that black boys who were vaccinated before age 3 were 3.4 times more likely to have autism than those who weren’t. The journal Translational Neurodegeneration published his study, then quickly retracted it, citing concerns about Hooker’s “competing interests” and the validity of his methods and statistics.

And don’t overlook the biggest issue: Even if there was a problem with the 2004 Pediatrics study, an association found in a single study of children in one city would not overturn or cast doubt on the enormous body of evidence ruling out a link between vaccines and autism.

Why has the conspiracy theory had such staying power? 

The short answer: It has the right ingredients — a whistleblower, a government coverup, children at risk — to catch fire in a distrustful community.

Critics also say the CDC hasn’t done a good job refuting the allegations.

The CDC put out a bland statement restating its research conclusions when the conspiracy theory first started to circulate in the summer of 2014. It hasn’t made its raw data available to the public. And it has not publicly responded to the allegations during the hubbub over the documentary.

CDC spokeswoman Sharon Hoskins didn’t respond to questions about that silence, though she did say an internal review of Thompson’s concerns about the 2004 Pediatrics study is ongoing.

Original article from: www.statnews.com