A one-year-old infant who died from Covid-19 had a concentration of the virus in just a small part of the brain, suggesting it may have a limited ability to reproduce there, according to Brazilian researchers.But it could still cause infection and trigger an excessive immune response that would damage brain tissue, according to the study, led by neuroscientist Stevens Rehen from the Federal University of Rio de Janeiro.The researchers concluded that the coronavirus “does not efficiently spread…