Starbucks said that rising supply and staffing costs connected to the Omicron variant took some of the luster off it quarterly performance, even though sales improved 13 percent on a two-year basis. “Prior to the emergence of the Omicron variant, we were experiencing some inflationary pressures and staffing issues resulting from the broader pandemic,” CEO Kevin Johnson said. “When the Omicron surge began, inflationary costs and staffing shortages were amplified, well in excess of our expectations.”