Boris Johnson, the former British prime minister, struggled to come to grips with much of the science during the coronavirus pandemic, his chief scientific adviser said Monday.

In keenly awaited testimony to the country’s public inquiry into the COVID-19 pandemic, Patrick Vallance said he and others faced repeated problems getting Johnson to understand the science and that he changed his mind on numerous occasions.

“I think I’m right in saying that the prime minister gave up science at 15,” he said. “I think he’d be the first to admit it wasn’t his forte and that he struggled with the concepts and we did need to repeat them — often.”