A mass vaccination event in Lincoln that helped Nebraska record one of its most productive days in its campaign to distribute shots could serve as a model for future events. Health officials in Lincoln said roughly 2,400 health care workers received the vaccine Friday at the event held at the Pinnacle Bank Arena. That helped the state administer 8,701 doses of the vaccine on Friday in what was the second-busiest day of the campaign so far. The state has been averaging about 4,500 shots a day over the past two weeks as it works to speed up distribution of the vaccine.