Tracking the emergence of disparities in the subnational spread of COVID-19 in Brazil using an online application for real-time data visualisation: a longitudinal analysis by Mee, P, Alexander, N, Mayaud, P, González, FDJC, Abbott, S, De Souza Santos, AA, Acosta, AL, Parag, KV, Pereira, RHM, Prete, CA, Sabino, EC, Faria, NR, Brady, OJ