This week, vaccine skeptic Robert F Kennedy Jr announced that he’d been nominated by President Elect Donald Trump to chair a commission on vaccine safety. A few hours later, the transition team issued a statement saying that that Trump was “exploring the possibility of forming a committee on autism”. Last summer, Trump met with Andrew Wakefield, who lost his medical license and was found to have produced fraudulent research linking vaccines to autism. Whether Trump is creating a commission on vaccine safety or autism, the message is clear. Trump is offering prominent support to the conspiracy theory that vaccines cause autism.

The science on vaccines is very clear: they are safe and effective. Vaccines do not cause autism. It’s a waste of our tax dollars to rehash this issue yet again. Vaccines are one of the greatest triumphs of modern medicine. Let’s consider measles, just one of many vaccine-preventable diseases. Before 1963, when the measles vaccine became widely available, 3-4 million Americans got measles each year, of whom 48,000 were hospitalized, 4000 developed encephalitis resulting in long-term brain damage, and 4-500 died. The country’s population has almost doubled since that time.

Trump and others have advocated delaying and spacing out vaccinations. But it’s important to understand that vaccination schedules are based on our scientific understanding of the immune system and disease transmission. A mother passes antibodies to her baby through the placenta as well as breast milk, thereby protecting her child against some infections. These antibodies don’t last forever. If you vaccinate a baby too early, the mother’s antibodies prevent the vaccine from taking effect. But if you wait too long to vaccinate, you leave the child unprotected. For example, studies have shown that by six months of age, over 95% of infants have lost the protection of their mother’s antibodies to measles.

At least until now, we’ve reaped the benefits of high vaccination rates: far less measles than in other parts of the world. When a disease becomes less common, the probability that you’ll come into contact with it goes down, actually giving us more wriggle room in our vaccination schedule. The measles vaccine also works a bit better if you wait until 12 months of age. But if you wait to vaccinate against measles until you’ve got a walking, talking toddler who’s around other kids, you’re putting that child at risk. Moreover, in the past two decades, more and more parents have chosen not to immunize their children, so much so that vaccination rates in some parts of the country are well below those seen in much poorer developing countries.

Parents want to do what’s best for their children. But in many cases, parents’ attitudes about vaccination have little to do with their understanding of the science and are driven by their distrust of the government on the right and the pharmaceutical industry on the left. Lack of trust in government – specifically its ability to create and sustain well-paying jobs in this country – helped elect Trump. As distrust in public institutions rises, conspiracy theories abound. Saying “I don’t believe you” is a way of saying “I don’t trust you,” no matter how much science there is to support a specific policy or course of action.

This isn’t the first time we’ve seen conspiracy theories proliferate about medical science – and it won’t be the last.

I spent two months as an aid worker in Guinea during the Ebola epidemic. In that time, I learned far more about the politics of science and medicine than about the virus itself. West Africans have very little trust in their public institutions – for good reason. These are among the most corrupt, least democratic nations in the world. And they have reason not to trust foreigners: a long history of slave trading followed by the stripping of natural resources for the profit of multinational corporations. We heard on the news that West Africans resisted recommendations about hand washing, safe burials, contact tracing and quarantines. On the ground, they told me that public officials were using the epidemic for political purposes and that expats were mercenaries. Yet we in the West dismissed their cynicism as primitive superstition.

President Elect Donald Trump has been a vocal proponent of numerous other conspiracy theories – about climate change, the media, our elections, Obama’s place of birth, the government’s role in the 9/11 attacks, the Deepwater Horizon oil spill, and the deaths of White House deputy counsel Vince Foster and Supreme Court Justice Antonin Scalia – to name just a few. As these false stories circulate, people lose trust in all institutions, especially the government and the media.

For now, Americans still trust scientists to act in the public’s best interest. We have a duty to live up to their trust. The lives of many Americans, our country’s future and the world’s are at stake.