Simon Wood and Ernst Wit have published a paper on making inference about Covid-19

Was R < 1 before the English lockdowns? On modelling mechanistic detail, causality and inference about Covid-19.

Simon Wood and Ernst Wit have published a paper in PLOS1 independently replicating and critiquing a major modelling study, from Neil Ferguson's Imperial College group, on the Covid-19 epidemic in England. By moving key model parameters back to literature based values, and by allowing more freedom for data, not assumption, to determine how R changes through time, the paper shows that R most likely dropped below one before either of 2020's full lockdowns. This result is consistent with direct statistical measurements, but reverses Imperial's own headline conclusions.

Wood SN, Wit EC (2021) Was R < 1 before the English lockdowns? On modelling mechanistic detail, causality and inference about Covid-19. PLoS ONE 16(9): e0257455. https://doi.org/10.1371/journal.pone.0257455