NEW YORK — U.S. stocks tumbled Friday as the “Trump bump” that Wall Street got from last week’s presidential election, along with a cut to interest rates by the Federal Reserve, kept fading.

The S&P 500 dropped 1.3% for its worst day since before Election Day to close out a losing week. The Dow Jones Industrial Average fell 305 points, or 0.7%, and the Nasdaq composite sank 2.2%.

Makers of vaccines helped drag the market down after President-elect Donald Trump said he wants Robert F. Kennedy Jr., a prominent anti-vaccine activist, to lead the Department of Health and Human Services. Moderna tumbled 7.3%, and Pfizer fell 4.7% amid concerns about a possible hit to profits.

Kennedy still needs confirmation from the Senate to get the job, and some analysts are skeptical about his chances. “However, if Kennedy is confirmed, it is hard to bookend risks for investors as his views are so outside the traditional Republican health policy orthodoxy,” Raymond James analyst Chris Meekins wrote in a research note. Meekins is a former deputy assistant secretary at the department known as HHS.

“Investors may need to forget everything they thought they knew about Republicans and healthcare,” Meekins said. “Kennedy’s appointment may make it less likely traditional qualified experienced (Republican) staff will agree to join HHS, creating more uncertainty.”

Biotech stocks broadly sank to some of the market’s worst losses, but the sharpest drop in the S&P 500 came from Applied Materials. It fell 9.2% even though it reported a stronger profit for the latest quarter than analysts expected.

The provider of manufacturing equipment and services to the semiconductor industry gave a forecasted range for upcoming revenue whose midpoint was short of analysts’ expectations.

The pressure is on companies to deliver big growth, in part because their stock prices have been rising so much faster than their earnings. That’s made the broad stock market look more expensive by a range of measures, which has critics calling for at least a fade. The S&P 500 is still up 23% for the year and not far from its all-time high set on Monday, despite this past week’s weakness.

Stocks had been broadly roaring since Election Day, when Trump’s victory sent a jolt through financial markets worldwide. Investors immediately began sending up stocks of banks, smaller U.S. companies and cryptocurrencies as they laid bets on the winners coming out of Trump’s preference for higher tariffs, lower tax rates and lighter regulation.

But investors are also taking into account some of the potential downsides from Trump’s return to the White House.

Besides Friday’s hit to vaccine makers, Treasury yields have been climbing on both the economy’s surprising resilience and worries that Trump’s policies could spur bigger U.S. government deficits and faster inflation.