NEW YORK, Dec 9 (Reuters) - Several Wall Street firms are increasing efforts to ensure staff get coronavirus booster shots, after Jefferies Financial Group Inc (JEF.N) reported a surge in COVID-19 cases and as countries and industries grapple with how to respond to the spread of the Omicron variant. Daily COVID-19 cases in New York City have surged in recent days and hospitalizations in the city are at their highest level since April, according to data from the U.S. Centers for Disease Control and Prevention (CDC). While the Delta variant is still dominant in the United States, Omicron has been detected in many U.S. states including New York.Most banks are strongly recommending staff get booster shots, sources said. Deutsche Bank (DBKGn.DE) has made COVID-19 boosters available to staff at its new headquarters in Columbus Circle since early November, according to a source familiar with the matter.Wells Fargo & Co (WFC.N) said on Wednesday it was providing all employees with four hours of paid leave to get the booster shot. JPMorgan Chase & Co (JPM.N) and Bank of America Corp (BAC.N) also provide employees with paid time off to receive vaccines and booster shots. U.S. private equity group KKR & Co Inc (KKR.N), headquartered in midtown Manhattan, also said on Thursday it was encouraging staff to obtain boosters. The firm sent notices to staff before Thanksgiving and after the Omicron variant was discovered, a spokeswoman said. The firm is also testing staff coming into the office for COVID-19 even if they are fully vaccinated and requiring masks in all common areas, the spokeswoman said. Banks and other financial firms are reluctant to reverse efforts since the summer to move staff who had been working from home back into the office. However, they are conscious that workers are increasingly concerned about the Omicron variant. On Wednesday, Jefferies asked staff to work from home again due to a spate of COVID-19 cases, throwing the issue of office versus home working back into focus. read more Some Jefferies staff were surprised by the news and had been unaware of any fresh wave of cases, they told Reuters. Jefferies did not respond to requests for further comment. Banks and other financial firms are mostly allowing smaller teams to hold holiday parties to help maintain morale, but avoiding large-scale, firm-wide gatherings. Several firms are requiring COVID tests before parties, the sources said. Some events have gone ahead. The UJA-Federation of New York"s Wall Street Dinner, attended by Wall Street leaders including Goldman Sachs (GS.N) Chief Executive David Solomon, was held on Monday at the Marriott Marquis in midtown Manhattan, attended by 700 in-person guests. Although proof of vaccination was required upon entry, in line with City of New York regulations, there was no requirement to mask and most guests chose not to as they mingled over hors d"oeuvres and cocktails.