Enthusiasm for Club holding Eli Lilly needs to be tempered — at least for now — as Wall Street grapples with the possibility of a major shakeup to health policy in Washington. The news Republican President-elect Donald Trump on Thursday nominated prominent vaccine skeptic and obesity-drug critic Robert F. Kennedy Jr.

to lead the Department of Health and Human Services . HHS, for short, is the sprawling agency that sits atop the Food and Drug Administration, Centers for Disease Control and Prevention, and Centers for Medicare & Medicaid Services, among other divisions. The cabinet-level position of HHS secretary requires confirmation by the Senate, where the Republicans will have a 53-seat majority, while the Democratic caucus will be 47.

Some members of the GOP, such as Kentucky Sen. Rand Paul, congratulated Kennedy on his nomination. But at this point, it's unclear whether Kennedy will be able to reach the 50-vote threshold for confirmation.

Shares of obesity drugmaker Eli Lilly fell more than 4% on Friday, extending a roughly 3% slide in Thursday's session. Media reports of Kennedy's nomination surfaced in the late afternoon Thursday, and Trump confirmed the decision in a social media post after the closing bell. Eli Lilly's main competitor in the obesity market, Danish firm Novo Nordisk , also saw its stock drop more than 4% on Friday.

Shares of Covid-19 vaccine makers including Moderna and Pfizer sold off late Thursday and again in Friday's session. A popular exchange.