New online tool can calculate Covid-19 transmission risk in poorly-ventilated places January 21, 2021 × Scientists agree that the vast majority of Covid-19 cases are spread through indoor transmission, whether via aerosols or droplets Researchers from the University of Cambridge and Imperial College London have quantified the role of ventilation in Covid-19 infection spread. They have found that in poorly-ventilated spaces, the virus spreads further than two meters in seconds, and is far more likely to spread through prolonged talking than through coughing. The results, reported in the journal Proceedings of the Royal Society A and Science Daily, revealed that social distancing measures alone do not provide adequate protection from the virus.