What happened: Moderna (MRNA) stock rose 8% in premarket on Monday, extending its 12% rally on Friday.

What’s behind the move: The biotech is researching vaccines to protect against hantaviruses, a group of viruses that spread to humans through exposure to rodents.

Biotech and vaccine stocks could also be volatile on Monday on reports that President Trump plans to let go of Food and Drug Administration commissioner Marty Makary. The move could open the way for easing regulation.

What else you need to know: A cluster of hantavirus cases was linked to the MV Hondius Dutch cruise ship in May 2026. Several people became seriously ill, and at least three deaths were reported.

Some of the passengers, including one American evacuated from the cruise ship hit by the deadly outbreak, have tested positive for the Andes strain of the virus, according to AFP.

Prior to the outbreak, Moderna was already conducting early-stage research on hantavirus in conjunction with the Vaccine Innovation Center at Korea University College of Medicine.

The stock extended gains from last week when the biotech also announced positive phase 3 study results for mRNA-1010, its seasonal influenza vaccine candidate.

Ines Ferre is a senior business reporter for Yahoo Finance. Follow her on X at @ines_ferre.

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