Scientists Discover How to Block Flu Before It Enters Cells

Scientists stumbled onto a discovery that could change how we prevent the flu, and it happened completely by accident.

Researchers at the University of Vermont were studying how influenza viruses replicate inside cells when they noticed something unexpected. The two most common flu strains, H1N1 and H3N2, were breaking into lung cells using completely different strategies.

Dr. Emily Bruce and her team made the breakthrough while examining viruses collected from patients who tested positive for flu in 2022. They were trying to understand how viral proteins move within cells to make new virus particles when they discovered a cellular pathway that could actually block the viruses from entering lung cells in the first place.

The team found that when they depleted a specific protein called Rab11B, the H3N2 virus couldn't enter human lung cells. The H1N1 virus, however, got in just fine without needing that protein.

This was a revelation. For years, scientists assumed all flu viruses entered cells the same way.

"We had previously thought that all flu viruses used the same way to get into a cell, but we discovered that this is not true," Bruce explained. She compared it to pirates from different countries hijacking a ship, each using different methods to get onboard.

The discovery matters because right now, flu tests don't distinguish between H1N1 and H3N2, and treatments are identical for both. While vaccines help prevent infection and antiviral drugs can shorten illness, Bruce says there's a "dire" need for better medications that stop flu viruses from replicating and spreading to new cells.

Why This Inspires

This accidental finding opens a door that researchers didn't even know existed. By identifying the specific proteins each virus needs to break into cells, scientists can now think about developing targeted therapies that block viral entry before infection takes hold.

The team is already planning next steps to determine whether this Rab11B dependency is a fundamental property of H3N2 or specific to currently circulating strains. Either way, the research provides what Bruce calls "fundamental insights" into how seasonal flu infects people.

Bruce's hope is simple but powerful: "Fundamental, curiosity-based research like this helps to pave the way for novel strategies to treat and prevent influenza infections."

Sometimes the biggest breakthroughs come when we're looking for something else entirely.