By Aislinn Laing
RIO DE JANEIRO, BRAZIL - Chile is shifting its COVID-19 vaccination strategy toward issuing second doses, while slowing administration of new shots, due to concerns over supply shortages and data showing scant protection from one dose of the Sinovac Biotech vaccine that formed the backbone of its campaign.
The Andean nation, which has had one of the world's leading Covid-19 vaccination programs, has put more than 13 million shots into arms, and by Monday had about 2 million doses left in its warehouses, according to official figures.
At present, clinics are doling out an average . . .