Here are some significant developments:
- Two dozen world leaders joined the World Health Organization on Tuesday to call for a global pandemic treaty that would prepare future generations for a health emergency similar to covid-19.
- Chancellor Angela Merkel said Germany will halt the use of AstraZeneca’s vaccine for people under 60 over concerns that it is causing rare but occasionally deadly blood clots.
- World Health Organization Director-General Tedros Adhanom Ghebreyesus questioned whether China had been transparent enough about the coronavirus’s origins and suggested that more research may be needed.
- Former president Donald Trump responded to criticism of his coronavirus policies by his health officials with a caustic statement ridiculing them as “self promoters” with “bad instincts and faulty recommendations.”
- The Pfizer-BioNTech and Moderna vaccines were 90 percent effective at preventing infections in a real-world study from the Centers for Disease Control and Prevention. It was one of the first to estimate vaccine effectiveness among participants against any infection — rather than just monitoring for symptomatic cases.