Covid-19 infections are on the rise, with most US states reporting an increase in cases. According to the US Centers for Disease Control and Prevention, the highly contagious BA.2.1.21 subvariant of Omicron is now the dominant strain of coronavirus nationwide.Covid-19 infections are on the rise, with most US states reporting an increase in cases. According to the US Centers for Disease Control and Prevention, the highly contagious BA.2.1.21 subvariant of Omicron is now the dominant strain of coronavirus nationwide.