Jan 17 (Reuters) - Moderna Inc"s (MRNA.O) vaccine candidate against the Omicron coronavirus variant will enter clinical development in the next few weeks and the company expects to be able to share data with regulators around March, CEO Stephane Bancel said on Monday. "The vaccine is being finished ... it should be in the clinic in coming weeks. We are hoping in the March timeframe to be able to have data to share with regulators to figure out next steps," Bancel said at the World Economic Forum"s virtual Davos Agenda conference. Moderna is also developing a single vaccine that combines a booster dose against COVID-19 with its experimental flu shot. (https://reut.rs/3FAeyya) Bancel said the best case scenario was the combined COVID/flu vaccine would be available by the fall of 2023, at least in some countries. "Our goal is to be able to have a single annual booster so that we don"t have compliance issues where people don"t want to get two to three shots a winter." Many countries are already offering a third dose of a COVID-19 vaccine to their citizens, especially to older individuals and those who are immunocompromised, while Israel has started offering its citizens a fourth dose. Earlier in January, Moderna"s CEO said people may need a fourth shot in the fall of 2022 as the efficacy of boosters against COVID-19 was likely to decline over the next few months. However, booster programs have met with skepticism from some disease experts over whether, and how widely, additional doses should become available, including the European Union"s drug regulator, which has expressed doubts about the need for a fourth booster dose. Speaking at the same event, top U.S. infectious disease expert Anthony Fauci said there was no evidence that repeat booster doses would overwhelm the immune system. "Giving boosters at different times, there is really no evidence that"s going to hinder (immune response)." Fauci said the goal should be to have a booster that induces a response against multiple potential variants.