Shares of the major vaccine makers rose on Monday as China battles its worst Covid outbreak since 2020, fueling fear that the pandemic will drag on which could drive demand for future vaccine orders.

Moderna’s stock jumped more than 8% to close at $150.07. In the morning, the biotech company’s stock had surged nearly 20% to hit an intraday high of $166.75.

BioNTech soared 12% to close at $151.92, Pfizer jumped 4% to $52.25, and Johnson & Johnson rose more than 1% to $171.69. Novavax turned negative and closed down more than 1% at $71.93, after jumping nearly 15% in the morning to hit an intraday high of $83.25.

The vaccine makers’ stocks rose even as the broader market fell, with traders monitoring the impact of the war in Ukraine and anticipating a rate hike by the Federal Reserve this week.

Major cities in China have placed fresh restrictions on business activity to fight the outbreak, driven by the omicron Covid variant. Shenzhen, a major tech hub in southern China, has told companies to halt all non-essential business activity or have employees work from home, while Changchun in the northeast has entered a lockdown. Apple supplier Foxconn has halted production in Shenzhen, while Toyota and Volkswagen have suspended production in Changchun.

In Shanghai, China’s financial hub, schools have gone back to online classes and officials told residents not to leave the city unless absolutely necessary. China has a strict zero-Covid strategy that uses tough measures to quickly stamp out outbreaks.

Mainland China reported more than 1,400 new Covid infections as of Sunday for a total of over 8,500 domestically transmitted cases, according to China’s National Health Commission. While low by international standards, it’s the most in China since March of 2020. China has not reported any new Covid deaths.

Jefferies’ analysts, in a note on Monday, said the outbreak and lockdowns in China have fueled fear among investors that the pandemic will take longer to resolve than expected.

“Vaccine makers will continue to trade on global fear of more waves,” Michael Yee, an equity analyst, wrote in the Monday note.

While China will likely continue to rely on its domestic vaccine Sinopharm, the outbreak will keep the world on alert and probably drive demand for Moderna’s vaccine on the margins, according the Jefferies’ note. Moderna is projecting at least $19 billion in vaccine sales for 2022, while Pfizer is projecting $32 billion in revenue for its shots.

In the U.S., Covid infections continue to decline after an unprecedented surge of infection driven by the omicron variant in December and January. The U.S. reported an average of more than 35,000 new Covid cases on Sunday, a 24% drop from the week prior, according to a CNBC analysis of data from Johns Hopkins University. New Covid cases in the U.S. peaked at an average of more than 800,000 cases a day on Jan. 15. However, more than 1,200 people are still dying every day on average from Covid in the U.S., though that’s down 9% from the week prior, according to the data.

The Centers for Disease Control and Prevention said last week that 98% of people in the U.S. now live in areas where they no longer need to wear facemasks in indoor public places.