Print Four months to the day after the first coronavirus vaccine doses went into arms in San Diego County, everyone age 16 and older now qualifies, as of Thursday, to sign up for the quick stick that increasingly governs where people can go when they leave their homes. It’s a particularly heady milestone given skepticism among many experts that getting any meaningful vaccine supply was likely in the first half of 2021. How far things have come since those first Pfizer doses were administered to health care workers on Dec. 15, 2020. Just four months ago, the road to herd immunity seemed endless with more than a million people with special circumstances — either due to their age, employment status or medical condition — in line to get their shots before anything came available for the rest.