As a result of the COVID-19 Omicron variant, on November 26, 2021, President Biden signed a proclamation suspending the entry of certain non-citizens traveling as immigrants or nonimmigrants who were present in Botswana, Eswatini, Lesotho, Malawi, Mozambique, Namibia, South Africa, and Zimbabwe during the 14-day period prior to their entry or attempted entry into the U.S. The suspension took effect at 12:01 AM EDT on Monday, November 29, 2021. U.S. citizens and lawful permanent residents (LPR, aka “green card” holders) are not subject to the proclamation.
Other exceptions include, but are not limited to: foreign diplomats traveling to the United States on A or G visas, and certain immediate family members of U.S. citizens or lawful permanent residents including spouses, children (under the age of 21), parents (provided that his/her U.S. citizen or lawful permanent resident child is unmarried and under the age of 21), and siblings (provided that both the sibling and the U.S. citizen or lawful permanent resident are unmarried and under the age of 21). There is also an exception for air and sea crew traveling to the United States on C, D, or C1/D visas. For the full list of exceptions, please refer to the proclamation.
Source: The U.S. DOS