WASHINGTON: US biotech firm Moderna on Monday announced its experimental vaccine against Covid-19 was almost 95 percent effective, marking a second major breakthrough in the quest to end the pandemic.Moderna released early results from a clinical trial with more than 30,000 participants, after American pharmaceutical company Pfizer and its German partner BioNTech last week said their vaccine was 90 percent effective.Both frontrunners are based on new technology that uses synthetic versions of...