With stories of the Omicron variant permeating the news, it remains to be seen whether this "cause for concern" (in President Joe Biden's words), might be a new tool for the Occupational Safety and Health Administration (OSHA) to use to uphold its Nov. 5 emergency temporary standard (ETS). The ETS requires employers who have at least 100 employees to institute either a mandatory COVID-19 vaccination policy or a weekly testing and mask-wearing policy for their employees. In the days following the establishment of OSHA's ETS, the U.S. Court of Appeals for the Fifth Circuit took the mandate to task, issuing a stay against its enforcement until further court order. Now, with the U.S. Court of Appeals for the Sixth Circuit in line to hear the next challenges to the ETS enforcement, a potential watershed legal battle stands in the way of the Biden administration's efforts to get the United States' population fully vaccinated to the degree originally anticipated.