A second dry run for COVID-19 vaccination will be held in all the states on Friday, sources have said. The first massive dry run was held on January 2. The exercise checked the best way to vaccinate people against COVID-19 and plug loopholes in logistics and training. The day-long drive on Friday will again test the operational feasibility of CoWIN application in a field environment. Short for Covid Vaccine Intelligence Network, CoWIN is a digital platform to roll out and scale up the vaccination drive.