For other infections, no vaccines are available. For EBV, a nearly ubiquitous virus with a long, clearly documented history of contributing to cancer, “we don't have an effective vaccine yet, or an effective way of preventing it,” says Rumgay. “This is something that we want to highlight with our study.” 

Historically, it was difficult to interest pharmaceutical companies in vaccines for viruses like EBV that are common and nonlethal, says Lawrence Young, a virologist and emeritus professor of molecular oncology at University of Warwick in the U.K. who has spent his career studying cancer and EBV. (Young was not involved in the IARC research.)

But thanks in part to research suggesting EBV might be involved in multiple sclerosis, an autoimmune disorder, “they've all become very interested,” he says. A number of vaccine candidates are now being studied, with some in clinical trials. 

For some of the infections implicated by the latest study—the Kaposi-sarcoma associated herpes virus, in particular—there’s need for much more research into prevention, says Rumgay. The hope is that “these new findings might stimulate more development in that area,” she says.