WASHINGTON, Nov 3 (Reuters) - U.S. private employers maintained a solid pace of hiring in October, though worker shortages linger. Private payrolls increased by 571,000 jobs last month, the ADP National Employment Report showed on Wednesday. Data for September was revised down to show 523,000 jobs added instead of the initially reported 568,000. Economists polled by Reuters had forecast private payrolls would increase by 400,000 jobs. The ADP report is jointly developed with Moody’s Analytics and was published ahead of the Labor Department’s more comprehensive, and closely watched employment report for October on Friday. But it has a dismal record predicting the private payrolls count in the department’s Bureau of Labor Statistics (BLS) employment report because of methodology differences. Economists expect hiring picked up in October, though persistent worker shortages remain a challenge. There were 10.4 million job openings at the end of August. Labor market indicators mostly improved in October as the summer wave of COVID-19 infections driven by the Delta variant subsided significantly. Initial claims for unemployment benefits have dropped below 300,000 for the first time since the coronavirus pandemic barreled through the United States about 20 months ago. The Conference Board’s labor market differential - derived from data on consumers’ views on whether jobs are plentiful or hard to get - hit a 21-year high. The Institute for Supply Management’s measure of factory employment also rose. According to a Reuters survey of economists, private payrolls likely increased by 400,000 jobs in October. With government hiring anticipated to have rebounded by 50,000, that would lead to overall payrolls rising by 450,000 jobs. The economy created 194,000 job in September, the fewest in nine months. Labor supply has remained tight despite the expiration of federal government-funded unemployment benefits, which businesses and Republicans had argued were a disincentive for the jobless to seek work. (Reporting By Lucia Mutikani Editing by Chizu Nomiyama)