With last week’s paper from Moderna, results from that same group of people finally had their formal publication. At the same time, the group registered a 30,000-person phase 3 clinical trial, specifying a pair of 100-microgram injections of the Covid-19 vaccine. According to the press release from May, there were no serious adverse events for the people in that particular dosage group. But last week’s paper shows the full results: By the time they’d had two doses, every single one was showing signs of headaches, chills or fatigue; and for at least 80 percent this could have been enough to interfere with their normal activities. A participant who had a severe reaction to a particularly high dose has talked in detail about how bad it was: If reactions even half as bad as this were to be common for some of these vaccines, they will be hard sells once they reach the community—and there could be a lot of people who are reluctant to get the second injection.