Almost £7 billion was wiped from the combined market values of GSK PLC and AstraZeneca PLC on Friday after Donald Trump unveiled his new health secretary.
President-elect Donald Trump announced the controversial appointment of Robert F Kennedy Junior, an outward anti-vaxer, on Thursday.
Trump said the new Department of Health and Human Services head had the “most important role” in any administration.
“[He] will play a big role in helping ensure that everybody will be protected from harmful chemicals, pollutants, pesticides, pharmaceutical products and food additives,” Trump added.
AJ Bell analyst Russ Mould noted investors had been spooked by the appointment of a “vaccine-sceptic” to the role.
“The impact on the sector is hard to judge fully at this stage but, at the very least, it will cause a good deal of uncertainty,” he said.
Jab-maker GSK subsequently fell 4.5% on the news, while peer AstraZeneca dropped 2.8%, equating to billions of pounds in market value.
Pharmaceutical companies elsewhere across the world also faced a blow on the news.
Germany’s Roche and Demark’s Novo Nordisk were among those to drop, as Moderna Inc and Pfizer Inc slumped 4% and 6% respectively across the Atlantic.