Leo Panitch was a political scientist by academic label but, maybe because of his Marxist orientation, a lot of his work was deeply historical, including his magnum opus, The Making of Global Capitalism of 2012. He was ill with cancer when he contracted Covid-19 in hospital on December 19.
Panitch was part of the early boomer generation of scholars. He came of age when universities and academic jobs were expanding rapidly. Born in Winnipeg, just as the Second World War ended, to a Jewish socialist immigrant family, Panitch was all through his apprenticeship (at the London School of Economics) by 1972 and secured a professorship at the age of 27, first at Carleton in Ottawa and from 1984 at York in Toronto. His first book was published in 1976 and he remained an active scholar, teacher, and journal editor all his life. He was widely influential and admired in Canadian progressive circles throughout his career. Wikipedia biography here.
There are probably other historians who have been part of the Covid death toll, but I think Panitch is the first I have heard of.