New research shows that two doses of an mRNA COVID-19 vaccine result in lower effectiveness for preventing hospitalization for the omicron variant (65%) than previous variants, including alpha (85%) and delta (85%). However, importantly, a third (“booster”) vaccine dose significantly improves protection against omicron hospitalization up to 86%.The almost year-long study, led by researchers at Vanderbilt University Medical Center, the Centers for Disease Control and Prevention (CDC) ...