Shares of major vaccine manufacturers took a sharp downturn after President-elect Donald Trump announced Robert F. Kennedy Jr. as his nominee to head the Department of Health and Human Services (HHS). Moderna’s stock closed more than 5 percent lower, Novavax fell over 7 percent, and Pfizer’s stock ended more than 2 percent lower on Nov. 14. BioNTech, the German drugmaker that helped develop a Covid-19 vaccine with Pfizer, closed more than 6 percent lower, while British drugmaker GSK, which makes flu shots and other vaccines, saw its shares dip roughly 2 percent, Fast Company reported.

The drop in vaccine maker stocks followed reports about Trump’s expected pick, with concerns mounting that Kennedy would promote his anti-vaccine rhetoric. Health policy experts worry that Kennedy’s stance could deter Americans from receiving routine immunizations. Kennedy has asserted that vaccines are linked to autism.

Kennedy, a former Democrat, is the founder of the nonprofit Children’s Health Defense, an anti-vaccine organization. Health officials have noted that vaccine skepticism and misinformation pose a significant risk to public health, especially in the midst of ongoing efforts to combat outbreaks and protect vulnerable populations.

Kennedy’s controversial nomination has been met with concern not only from experts but also from politicians. Democratic Congressman Robert Garcia of California’s 42nd district, for example, called the appointment “insane,” warning that it would “destroy our public health infrastructure and our vaccine distribution systems.” Meanwhile, the Make America Healthy Again PAC, which supports Kennedy, has celebrated his nomination as a chance to dismantle corporate influence over public health agencies.

The financial impact of Kennedy’s potential leadership of the HHS could ripple through the pharmaceutical industry. Companies like Moderna, Novavax, and Pfizer have already been struggling to recover from falling Covid vaccination rates, which have dented their profits over the past two years, CNBC reported.