Ku dhammee weedha soo socota: Xusuus-qorka John Snow, oo lagu daabacay "The Lancet", waa jawaab ay bixiyeen 80 cilmi-baare oo cambaareynaya habka difaacida kooxda ee Baaqa Great Barrington. magaciisana waxaa laga soo qaatay John Snow, oo ah cilmi baare ku xeeldheer cudurada faafa, kaasoo ka shaqeeyay cudurka
1854 Cudurka shuban biyoodka ee ka dillaacay wadada Broad Street, waxay sheegtay in fikradda difaaca jirka ay tahay "khalad khatar ah oo aan lagu taageerin caddeyn cilmiyeed". Waxay qiraysaa in xayiraadaha COVID-19 ay keeneen niyad jab, taas oo ka dhigaysa fikrad noocaas ah mid soo jiidasho leh, laakiin waxay sheegtay in "aysan jirin caddeyn ku saabsan difaaca difaaca ee waarta ee SARS-CoV-2", iyadoo ku dartay in "istiraatiijiyad noocan oo kale ah aysan horseedi doonin dhammaadka COVID-19, laakiin taa bedelkeeda ay keeni doonto cudurrada faafa ee soo noqnoqda, sida ay ahayd kiiska cudurrada faafa ee badan ka hor imaatinka tallaalka. "