CDC studies: Booster shots needed against Omicron

Three new U.S. studies showed more evidence that COVID-19 vaccines are standing up to the omicron variant, at least among people who received booster shots. It found vaccine effectiveness was best after three doses of the Pfizer or Moderna vaccines in preventing COVID-19-associated emergency department and urgent care visits.

Dr. Rochelle Walensky, CDC Director said "For both the Delta and Omicron variant, there was a decline in vaccine effectiveness against hospitalization over time. But following a third dose vaccine, effectiveness against hospitalization with Omicron increased to 90%, nearly matching the effectiveness against the Delta variant and even higher than vaccine effectiveness after the first two doses of the MRNA vaccine. Overall, for those who received a booster dose, had the most protection against emergency room visits, urgent care clinic visits and hospitalizations."

However, two doses offered no significant protection against omicron, the researchers found.