The news prompted a sell-off across the industry. In the US, shares in Pfizer and Moderna sank more than 5% in early trading, while UK-listed firms AstraZeneca and GSK dropped 2% or more. Russ Mould, investment director at AJ Bell, said the pick had “spooked” shareholders, despite questions about how the new administration might pursue its threats.

Kennedy Jr. suggested that the COVID-19 virus was engineered to give Chinese and Ashkenazi Jewish people immunity and the FDA "suppresses" advancements in human health.

Robert F. Kennedy Jr. wants to revisit federal vaccine recommendations, take fluoride out of public water and boost access to raw milk, among other goals.

Democratic Colorado Gov. Jared Polis praised President-elect Trump for nominating RFK Jr. to be the next secretary of the Department of Health and Human Services.

This isn’t the first time Polis, who is seen as a possible 2028 Democratic presidential contender, has shown a willingness to butt heads with his party.

President-elect Trump's decision to tap Robert F. Kennedy Jr as his nominee for secretary of Health and Human Services has elicited mixed reactions from Republicans on Capitol Hill. Why it matters: Kennedy — an anti-vaccine activist who previously ran against Trump for president before dropping out and endorsing him — will need to lock down support from key senators to get through the conformation process.