Vaccine stocks fall after FDA’s Peter Marks resigns over RFK Jr.

Shares of major vaccine makers dropped on Monday after a key U.S. health official resigned in protest of Health and Human Services Secretary Robert F. Kennedy Jr.’s views on immunization.

The departure of Peter Marks, the Food and Drug Administration’s top vaccine regulator, has raised fresh fears about whether the Trump administration will quickly approve and promote critical shots. In his position, Marks oversaw the introduction of Covid-19 vaccines and rules for using emerging treatments like cell and gene therapies.

Shares of Moderna and Novavax each closed greater than 8% lower Monday. Meanwhile, the SPDR S&P Biotech ETF slid nearly 4%.

Some Wall Street analysts said Marks’ departure could undermine the FDA’s mission of ensuring protected and effective treatments reach patients within the U.S. That might put much more pressure on a struggling biotech sector.

“Taking a step back, we view this departure as a major negative for the BioPharma and Biotech sectors, as FDA’s independence rooted in sound scientific rigor is critical for his or her efficient functioning,” analysts at BMO Capital Markets wrote in a note Monday.

In his resignation letter obtained by CNBC on Friday, Marks criticized Kennedy’s “misinformation and lies” about immunization. He said a growing measles outbreak that began in Texas got here as a consequence of “undermining confidence in well-established vaccines.”

“As you’re aware, I used to be willing to work to deal with the Secretary’s concerns regarding vaccine safety and transparency by hearing from the general public and implementing a wide range of different public meetings and engagements with the National Academy of Sciences, Engineering, and Medicine,” Marks wrote. “Nevertheless, it has develop into clear that truth and transparency are usually not desired by the Secretary, but reasonably he wishes subservient confirmation of his misinformation and lies.”

The Department of Health and Human Services didn’t immediately reply to a request for comment.

Kennedy, a distinguished vaccine skeptic, has already taken steps that public health experts say could deter routine immunizations within the U.S. He has downplayed the importance of the measles, mumps and rubella vaccine and promoted unproven treatments to counter the measles outbreak. The Centers for Disease Control and Prevention can also be carrying out a study into long debunked links between vaccines and autism, led by a researcher with a history of spreading misinformation about shots.

Analysts at Leerink Partners wrote in a Monday note that the effect of Marks’ resignation on biotech and pharmaceutical stocks will depend partly on who replaces him on the FDA and whether Republicans within the White House and Congress begin to lose patience together with his approach. Other analysts also stressed that Marks is simply one official on the agency and noted that latest FDA Commissioner Marty Makary has a track record of supporting proven treatments.

“Though many imagine the Marks resignation is a really bad omen for the Healthcare industry and innovation at large, it might be a bit premature to solid too dark of a shadow on everything of Pharma and Biotech,” wrote Mizuho Securities analyst Jared Holz.

— CNBC’s Angelica Peebles and Annika Kim Constantino contributed to this report