Imperial College London researchers found that Vaccinia viruses hop over cells that are already infected.

This allows them to concentrate their energies on previously uninfected cells, accelerating the spread of infection fivefold.

Vaccinia is known to spread from cell to cell in a characteristic way. After attaching to the cell membrane of its target, it releases a protein that enters the cell, where it communicates with actin — a protein that helps maintain the cell’s structure. The actin responds by growing longer, and then attaches itself to the virus, still sitting on the surface of the cell, as a so-called “actin tail.” This tail helps the virus take off from the cell and find the next victim.

Finding ways to block the cell surface proteins might lead to new antiviral drugs.