evidence: Did a report really say masks don’t help prevent the spread of COVID? [...] "It would be accurate to say that the review examined whether interventions to promote mask-wearing help to slow the spread of respiratory viruses, and that the results were inconclusive," she said. In March, Tom Jefferson, a British epidemiologist who was the lead author of the report, told a journalist that "there is just no evidence that they [masks] make any difference".