Tracking Variants and Viruses Over the weeklong period ending Saturday, the proportion of BA.5 cases decreased by 12.6 percent, while Omicron sublineages BQ.1 and BQ.1.1 rose to become the second and third most prevalent variants. The dominant variant: BA.5 (49.6% of US cases) Other variants: BQ.1 (14%), BQ.1.1 (13.1%) Source: Centers for Disease Control and Prevention Other top stories New research show that vaccinating pregnant women was nearly 82 percent effective at preventing severe cases of RSV in their babies during their first 90 days of life. This flu season is hitting hard and looks to be the most severe since 2009, according to federal health data reported by the Washington Post. There have been at least 880,000 influenza cases, 6,900 hospitalizations, and 360 flu-related deaths in the US, according to CDC data.