Health officials and vaccine makers call for boosters after studies show Pfizer vaccine is less effective against Omicron, but data on breakthrough cases suggest the vaccine hasn’t been effective against other strains, either.
Newly released report from the U.S. Department of Defense says Russia and China's newly expanded nuclear weapons arsenals and tactics have "increased potential for regional conflicts involving nuclear-armed adversaries in several parts of the world and the potential for adversary nuclear escalation in crisis or conflict."
