Overnight Health Care: UK coronavirus variant now most common strain in US | Over 500K sign up for ObamaCare in special period | EU finds ‘possible link’ between AstraZeneca vaccine, blood clots

Welcome to Wednesday’s Overnight Health Care. For those in the DC area looking for a shot, a new mass vaccination site opened at the Greenbelt metro station today. If you have any tips, email us at nweixel@thehill.com , psullivan@thehill.com…