NEW YORK (AP) — Three new U.S. studies offer more evidence that the COVID-19 vaccines are standing up to the omicron variant, at least among people who have gotten booster shots. The Centers for Disease Control and Prevention released the studies Friday. The results echo previous research — including studies in Germany, South Africa, and the United Kingdom. They found available vaccines are less effective against omicron than they were against earlier versions of the coronavirus. One of the papers found that two doses of the Pfizer and Moderna vaccines offered no significant protection against omicron. Several studies have concluded a booster can significantly improve protection.