ANGELA Rasmussen studies the interactions between hosts and pathogens and how they shape disease. Before the pandemic, she worked on the emerging viruses that cause Middle East respiratory syndrome (Mers), Ebola, dengue and avian flu. Then, when Covid-19 erupted, the American virologist, who works at the University of Saskatchewan in Canada, was drawn into the debate over where it came from. She has been among the most vocal scientists on Twitter defending a “natural” origin, as opposed to a lab leak. Last month, she and 17 co-authors published findings in Science that they feel should silence all rational critics on the question…

This article first appeared in The Observer on 14 August 2022. To continue reading, click here.