VALLETTA, Dec 23 (Reuters) - The Mediterranean islands of Malta became the latest European nation on Thursday to tighten COVID-19 restrictions as virus numbers hit a new record for a second successive day. Health Minister Chris Fearne said events where people could not be seated were being banned from Dec. 27 while sports events would have to be held behind closed doors. All venues have to close by 1.00 a.m. An open-air New Year"s Eve celebration in the capital, Valletta, was cancelled. Fearne said all those aged over 18 will be able to apply for vaccine booster shots from Dec. 27, and vaccination certificates will be necessary for entry to most venues from Jan. 17. Vaccination take-up in Malta stands at well over 90%, one of the highest in Europe. It recorded 733 new virus cases on Thursday, up from 582 on Wednesday. Fearne said the first two cases of the Omicron variant had been detected but added that he was confident it could be kept in check with booster shots.