BANGKOK, Dec 13 (Reuters) - Thailand will halve to three months the time between administering a second COVID-19 vaccine shot and a booster, a health official said on Monday, to try to strengthen immunity in anticipation of a local spread of the Omicron variant. Thailand has so far detected eight imported cases of the Omicron variant but has yet to see community transmission, according to its health ministry. Omicron has been reported in dozens of countries. "Because Omicron is now widespread, the booster third shot would help lessen the severity of symptoms and reduce the death rate," said Taweesin Wisanuyothin, spokesperson for the government"s COVID-19 taskforce. Taweesin said recipients of a second shot in August or September could get boosters right away at any vaccine centre nationwide. The UK Health Security Agency on Friday said boosters significantly restored protection against mild diseased caused by the Omicron variant, in early findings from a real-world analysis. More than 43 million people or 60% of people in Thailand have received two doses of a COVID-19 vaccine, of which 4.1 million have received boosters.