Jan 14 (Reuters) - U.S. railroad operator Union Pacific Corp (UNP.N) said it was encouraging employees to work from home until Jan. 30, as the fast-spreading Omicron variant of the coronavirus forces companies to rethink bringing employees back to office. "We are still encouraging employees to report their vaccination status and get vaccinated," Union Pacific said in an emailed statement on Thursday. The company, which operates in 23 states and connects East Coast ports to key terminals like Chicago, had suspended its COVID-19 vaccine mandate for employees last month after a judge blocked the Biden administration"s inoculation rule for federal contractors. read more About 73% of its 31,000 employees were fully vaccinated against COVID-19 as of Dec. 8, the U.S. railroad operator had said. Some U.S. companies are asking employees to work from home in a bid to prevent infection among staff as the Omicron variant rages through the country. 779,588 new COVID-19 cases were reported in the United States on average over the past week, a Reuters tally showed.