JERUSALEM—Israel’s Health Ministry has halted the national rollout of a fourth vaccine dose for those over 60 or at risk of severe disease that was set to begin on Sunday, opting instead for a hospital trial to address the debate over whether there is sufficient scientific information available to justify another booster drive. A major Israeli hospital will begin administering a fourth COVID-19 vaccine shot to 6,000 individuals, including 150 hospital staff, on Monday in a trial aimed at gauging whether a second booster is necessary nationwide, the facility said on Sunday. Sheba Medical Center near Tel Aviv said its trial would shed light on the efficacy and safety of a fourth dose and help decision-makers set health policy in Israel and abroad. “This study will test the effect of the fourth vaccine dose on the level of antibodies, on preventing contagion, and check its safety,” Gili Regev-Yochay, the study’s director at Sheba said. “This study …