Thailand will halve to three months the time between administering a second Covid-19 vaccine shot and a booster, a health official has said, according to Reuters.

The decision has been taken to try to strengthen immunity in anticipation of a local spread of the Omicron variant.

"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 task force.

Taweesin said recipients of a second shot in August or September could get boosters right away at any vaccination centre nationwide.