ILLUSTRATION of hantavirus testing concept with laboratory tubes containing cotton swabs and HANTAVIRUS labels photographed in front of a public domain hantavirus related microscopic image released by the U.S. Centers for Disease Control and Prevention in Paris, France, May 8, 2026.
Joao Luiz Bulcao | Afp | Getty Images
An outbreak of the hantavirus caused a brief spike in the stocks of companies working to develop a vaccine, but the stocks weren’t able to sustain their early gains.
The World Health Organization flagged an outbreak of hantavirus, a fatal and viral respiratory disease spread by rodents, on May 2, after some passengers caught it on a Dutch-flagged expedition cruise ship, the MV Hondius, which was sailing the Atlantic.
The public health risk for the virus is low, according to the WHO and other health authorities that have noted human transmission is rare.
Which pharma and biotech stocks are rising?
Biotech firm Moderna, which developed one of the main Covid-19 vaccines, was up less than 1% after it said it was conducting preclinical research on the virus. Shares had spiked as high at $59.48 earlier in the session.
“Moderna has conducted preclinical research on Hantaviruses in collaboration with the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), reflecting the ongoing regional impact of these pathogens,” it said in a statement shared with CNBC.
“These efforts are early-stage and ongoing and reflect Moderna’s broader responsibility to develop countermeasures against emerging infectious diseases.”
Evercore ISI said last week that it is unlikely to be a revenue opportunity for Moderna in the hantavirus case.
Moderna stocks year-to-date compared to several other pharma stocks.
“As a heavily retail-trafficked name, [Moderna] tends to trade on outbreak headlines well beyond the underlying commercial implications,” Evercore analysts said in the note published on May 7. “With regards to current headlines, we see no meaningful revenue opportunity.”
“Hantavirus is a low-incidence, structurally small market, and we view any potential outsized moves as sentiment-driven, not fundamental. At most, it reinforces Moderna’s mRNA platform agility, something already well understood post-COVID,” they added.
Meanwhile, vaccine development firm Inovio Pharmaceuticals fell 1%, while biotech firms Novavax and Emergent BioSolutions each fell 5% and 1%, respectively. All three stocks had seen gains in early trading.
U.S. President Donald Trump has said the cruise ship outbreak is under control and that a report on the virus would follow soon.
“It’s very much, we hope, under control,” Trump told reporters Thursday. “It was the ship, and I think we’re going to make a full report about it tomorrow. We have a lot of people. … It should be fine.”
What is hantavirus and how serious is the outbreak?
The Hantavirus strain in this case is the Andes virus, which is the only species that can cause transmission between humans, according to the WHO.
WHO’s Director General Tedros Adhanom Ghebreyesus said Friday that eight cases have been reported so far, with three deaths, and five of the cases confirmed as hantavirus. The WHO has assessed the “public health risk as low,” Ghebreyesus said.
The MV Hondius has now docked in Tenerife in Spain’s Canary Islands, after spending several days offshore awaiting clearance.
Passengers and crew have begun disembarking under strict health protocols, with authorities coordinating testing, isolation, and repatriation efforts across multiple countries as they continue to monitor the spread of the virus.
