WATCH: Here`s why you`ll need two doses of Covid-19 vaccine
(World News South Africa)

The three vaccine makers which are closest to widespread distribution, namely, AstraZeneca, Pfizer and Moderna, require two doses of the vaccine to work. A protective effect starts to develop 12 days after the first dose, but full protection requires a follow up shot, according to the World Health Organisation (WHO). The second dose is considered to be a booster and can be administered anywhere from three weeks after the first one to as much as three months...