Two COVID-19 vaccine trials are currently paused due to concerns about its side effects. AstraZeneca’s U.S. trial of its vaccine has been stalled for over a month after two volunteers developed neurological conditions, though it is unconfirmed how the conditions arose. Likewise, this Monday, Johnson & Johnson stated it would pause its vaccine trial to investigate an illness that arose in a participant. Both companies were developing vaccines based on adenoviruses, which are well-studied viruses and generally tolerated in vaccines in small doses, causing mild symptoms in most cases. Read the full article here.