Moderna /zigman2/quotes/205619834/composite MRNA -1.20% has begun testing an omicron-specific COVID-19 booster in healthy adults, following in the wake of a study announced earlier this week by Pfizer /zigman2/quotes/202877789/composite PFE +1.50% and German partner BioNTech /zigman2/quotes/214419716/composite BNTX -4.81% ,the Associated Press reported. The original vaccines still offer good protection against death and severe illness. Studies in the U.S. and elsewhere show a booster dose strengthens that protection and improves the chances of avoiding even a milder infection. The U.S. is averaging 618,231 cases a day, according to a New York Times tracker, down 21% from two weeks ago, suggesting the omicron peak has been reached. Hospitalizations at an average of 153,306 remain high, however, and deaths are averaging more than 2,466 a day, the most since last winter. On a global basis, the total tally for COVID-19 cases hiked up above 362.8 million and the death toll rose above 5.62 million, according to data aggregated by Johns Hopkins University. The U.S. leads the world with a total COVID-19 case count of 72.9 million and death toll of 876,066.