COVID-19 vaccine candidate got underway as states continue to roll out scarce supplies of the first shots to a nation anxiously awaiting relief from the catastrophic outbreak.Public health experts say more options in addition to the two vaccines now being dispensed — one made by Pfizer and its German partner BioNTech, the other by Moderna — are critical to amassing enough shots for the country and the world.The candidate made by Novavax Inc is the fifth to reach final-stage testing in the US.Also Read | How Indians lived online during 2020Some 30,000 volunteers are needed to prove if the shot — a different kind than its Pfizer and Moderna competitors — really works and is safe.“If you want to have enough vaccine to vaccinate all the people.