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

imitsi yekugoma yeco vid19 yendlula kunchubo lebitako, lenetigaba letinyenti tekuhlolwa, kufaka ekhatsi kulinga kwekusebenta kwayo lokutsatsa sikhatsi lesidze lokufaka ekhatsi tinkhulu ngwane letingemashumi shumi tebantfu.
