GENEVA—The World Health Organization says coronavirus case counts fell 17 percent worldwide over the last week compared to the previous week, including a 50 percent drop in the United States, while deaths globally declined 7 percent. The weekly epidemiological report from the U.N. health agency, released late Tuesday, shows that the omicron variant is increasingly dominant—making up nearly 97 percent of all cases tallied by the international virus-tracking platform known as GISAID. Just over 3 percent were of the delta variant. “The prevalence of the omicron variant has increased globally and is now detected in almost all countries,” WHO said. “However, many of the countries which reported an early rise in the number of cases due to the omicron variant have now reported a decline in the total number of new cases since the beginning of January 2022.” All told, WHO reported more than 19 million new cases of COVID-19 …