The impact of COVID-19 on clinical research for Neglected Tropical Diseases (NTDs): a case study of bubonic plague od Rasoanaivo, TF, Bourner, J, Randriamparany, RN, Gamana, TM, Andrianaivoarimanana, V, Raherivelo, MH, Randriamampionona, H, Rajerison, M, Raberahona, M, Salam, AP, Edwards, T, Olliaro, PL, Randremanana, RV