COVID-19 infections fell by 30% in England during the first three weeks of the second national lockdown imposed on November 5, according to a study by the Imperial College London released on Monday."Three weeks into the second national lockdown in England there has been a ~30% proportionate reduction in prevalence overall, with greater reductions in the North," the study said.Despite the improvements, which also saw the virus' reproduction rate -- the number of people that one infected person will pass on a virus to, on average -- fell below one, researchers said the epidemic should be kept under continued monitoring until prevalence is reliably reduced to much lower levels and a vaccine is found.The findings by Imperial College London come.