The new US president has said he believes that vaccines are harmful and has repeatedly and erroneously suggested that they cause autism. These claims are untrue and dangerous.

Back in 1998, British medical researcher Andrew Wakefield published a paper in the health journal The Lancet that claimed to show a link between children who were given the measles, mumps, and rubella vaccine with autism and bowel disease.

No other scientists were able to reproduce his results – something that is vital in research. Most of Wakefield’s coauthors withdrew their support for the study. After conducting an official inquiry, a tribunal of the British General Medical Council concluded that Wakefield acted dishonestly and irresponsibly and even performed unnecessary invasive medical procedures such as colonoscopies on the children.

The Lancet eventually retracted the paper, and Wakefield was struck from the UK medical register with a statement identifying that he had deliberately falsified scientific results.

By then, however, the damage had already been done. Many people in the US and Europe still believe that vaccinations cause illnesses and conditions including autism in children. Despite official medical advice that says vaccines are safe and vital, many parents still worry about inoculating their children. The belief is heavily ingrained in the minds of many.

According to a 2015 report by the Pew Research Center, about one in 10 Americans thinks vaccines are not safe. Among those is Robert F. Kennedy Jr., the nephew of John F. Kennedy.

Kennedy has pushed hard against the use of a chemical called thimerosal - a preservative used in vaccines to prevent the growth of bacteria and fungi that so-called antivaxxers often confuse with mercury. He also thinks parents should choose whether their children are vaccinated.

After a meeting at Trump Tower this month, Kennedy said Trump had "some doubts about the current vaccine policies and he has questions about it." He also said the president had asked him to chair a commission on vaccination safety, but Trump's team has since denied this.

Trump has previously used anecdotal examples to express his views on the matter.

"I've seen people where they have a perfectly healthy child, and they go for the vaccinations, and a month later the child is no longer healthy," Trump said on Fox in 2012. "It happened to somebody that worked for me recently. I mean, they had this beautiful child, not a problem in the world. And all of a sudden, they go in, they get this monster shot. You ever see the size of it? It's like they're pumping in - you know, it's terrible, the amount. And they pump this into this little body. And then all of the sudden, the child is different a month later. And I strongly believe that's it."

During the GOP debate in September 2015 he described that example again and suggested that vaccines were causing an "autism epidemic."

"People that work for me, just the other day, 2 years old, beautiful child went to have the vaccine and came back and a week later got a tremendous fever, got very, very sick, now is autistic," he said.

Contrary to those statements, there is no epidemic. It is true there are more cases; in the 1970s and 1980s, about one in 2,000 children had autism, but today the CDC estimates that one out of 150 8-year-olds in the US have it. But this is probably due to better diagnosis rather than anything else. And Trump's opinions of vaccines do not appear to be backed up by any sort of scientific research. More recently he has claimed to support vaccination but has argued that they should be given over an extended period of time.

This belief is also popular among those opposed to vaccines, but there is no scientific evidence supporting it. Vaccinations are given at set times after decades of doctors working out the best schedule.

Infants' immune systems don't get "overloaded" by vaccines - that's just not how it works. A single bacterium has 2,000 to 6,000 immunological components, and we encounter many bacteria every day. The total number of immunological components of all 14 vaccines given in the first years of life is about 160.

In fact, not getting vaccines on time can put children at risk. Infants can be easily exposed to nasty diseases because their immune systems are just getting started, and spreading vaccines out delays their protection. It also exposes young children to more visits to the doctor, potentially exposing them to contagious diseases. Also, if there is a long time between boosters, some parents forget to bring their children back.

Vaccinations eradicated smallpox, but antivaccination rhetoric appears to have kept this from happening to other diseases. Polio came close to eradication, but instances of it have cropped up in countries recently. In 2014, an epidemic of measles spread across Wales because of vaccine skepticism. Whooping cough was at an all-time low in the 1980s - 10 years after the vaccine was introduced - with 2,900 cases in the UK. After Wakefield's paper, this rose to 26,000 cases in 2004 and 50,000 in 2012.