SEOUL (Reuters) - South Korea more than tripled the number of coronavirus vaccine containers aircraft can carry by easing limits on dry ice needed to keep them cold, the country’s deputy minister for aviation told Reuters on Tuesday. South Korea said on Tuesday it signed deals to provide coronavirus vaccines for 44 million people next year, including from AstraZeneca Plc, Pfizer Inc, and Moderna Inc and Johnson & Johnson’s Janssen. Airlines and governments round the globe are working on ways to establish cold chain delivery systems for vaccines, like Pfizer’s, which requires storage at below minus 70 Celsius, and Moderna’s, which needs to be kept at -20C. A difficulty with vaccine transport is that airplanes can only carry a limited amount of dry ice - frozen carbon dioxide - as it turns into gas over time, displacing the breathable air in the cabin. The transport ministry raised the limit of dry ice a plane can carry from 3,300 to up to 11,000 kilogrammes, which will allow a Boeing 747 cargo plane to carry 52 containers of vaccines, up from 15, Kim Sang-do, deputy minister for civil aviation, said on the sidelines of a forum. To allow this, it will boost safety measures such as carbon dioxide emission inspection and installation of gas meters, the ministry said in a statement. “Vaccine transport is difficult due to the expertise and the steady temperature necessary,” Kim said, adding that the unbroken cold chain of temperature management could include a cold cargo facility the size of two soccer fields being built near the main international airport in Incheon. It is expected to be completed in February next year and operated by Korean Air, according to the ministry. United States’ Federal Aviation Administration (FAA) said last week that it supported its first mass vaccine air shipment, adding it is working to provide guidance on dry ice safety rules.