COLOMBO – Sri Lanka has approved the Oxford-AstraZeneca vaccine to be used against COVID-19 amid warnings from doctors that frontline health workers should be quickly vaccinated to stop the system from collapsing.Minister for Pharmaceutical Production and Regulation Channa Jayasumana said the British vaccine has been approved for emergency use, the first to be approved in Sri Lanka, while several other candidates are in the pipeline at the National Medicines Regulatory Authority.It is unknown when Sri Lanka might be able to get supplies.“Hundreds of health care workers are tested positive in several hospitals.