ALEXANDER WINNING TWO of the South African government's top advisers on COVID-19 backed Pfizer's vaccine on Friday, despite a study earlier this week showing that the dominant local coronavirus variant may reduce protective antibodies it triggers. The country is counting on the Pfizer shot, developed with German partner BioNTech, to step up its vaccination programme after administering its first Johnson & Johnson doses on Wednesday. Professor Barry Schoub AstraZeneca vaccinations are on hold after a small local trial found the shot offered minimal protection against mild to moderate illness from the 501Y.V2 variant first identified late last year. The laboratory…