Oct 21 (Reuters) - Chipotle Mexican Grill Inc (CMG.N) beat estimates for quarterly same-store sales on Thursday as COVID-19 vaccinations and its new menu items encouraged more people to dine out at its restaurants despite higher menu prices. Shares rose over 1% in after-market trading after the fast-casual chain posted a 15.1% surge in comparable sales for the quarter ended Sept. 30, compared with analysts" average estimate of 13.4% growth, according to Refinitiv data. The company also forecast sales growth in the low to mid double-digits range in the current quarter, compared with estimates of 14% growth. Even so, uncertainty about the impact of COVID-19, inflation and labor pressure persist. "While COVID impacts will likely persist for a few more quarters, we are hopeful that the worst is behind us and society can shortly return to a more normal environment," Chief Executive Brian Niccol said during a call with analysts. Americans who were cooking more in their kitchens during the pandemic-induced, work-from-home situation are now grabbing burritos and bowls on the way to work and social gatherings, and are trying new dishes. Chipotle has expanded its menu with items such as smoked brisket, cauliflower rice and carne asada while also raising the prices of its offerings to make up for higher payroll and ingredient costs. It is now testing plant-based chorizo, Niccol said.Digital orders - as opposed to those placed in person - grew 8.6% and accounted for 42.8% of sales. Those sales, the strong recovery of in-restaurant sales, and successful new menu items drove strong revenue growth, the company said in a statement. Chipotle also said its board increased its share repurchase authorization by $100 million, with $209.8 million available to buy back shares as of Sept. 30