covid19 vaccines go through a demanding, multistage testing process, including large trials that involve tens of thousands of people.

imigomo yecovid19 idlula kwinqubo enomsebenzi omkhulu, enezigabagaba zokuhlola, okubandakanya ukuhlolwa kokusebenza kwayo okufaka phakathi izinkulungwane eziyishumi zabantu.
