claim: moderna vaccine becomes the covid-19 vaccine approved by uk regulator.
evidence_1: moderna's vaccine marks the third to be approved for use by the mhra and the second that uses the mrna approach, which sends a message to cells telling them to create proteins that can generate an immune response.", "moderna's is the third shot that has been authorized for use in britain, following earlier approvals for the vaccines from pfizer and biontech and the university of oxford and astrazeneca.")