Nov 18 (Reuters) - Hong Kong stocks ended higher for a third straight session on Wednesday, with the automotive sector leading gains, as investors continued to cheer news of COVID-19 vaccine breakthroughs.

** Moderna Inc said this week its experimental vaccine was 94.5% effective in preventing COVID-19 based on interim data from a late-stage clinical trial, becoming the second U.S. company in a week to report results that far exceeded expectations. ** At the close of trade, the Hang Seng index was up 129.20 points, or 0.49%, at 26,544.29, while the Hang Seng China Enterprises index rose 0.85% to 10,640.05.

** The automotive sector was the top gainer in the market, led by Geely Automobile Holdings, which rose as much as 8.8% to its highest level since June 2018, before closing 6.9% higher.

** German car maker Daimler said on Tuesday it would cooperate with China's Geely to build next-generation combustion engines for use in hybrid vehicles. ** The biggest loser on the Hang Seng was WuXi Biologics (Cayman) Inc, which fell 1.92%. ** China's main Shanghai Composite index closed up 0.22% at 3,347.30 points, while the blue-chip CSI300 index ended down 0.06%.

** Around the region, MSCI's Asia ex-Japan stock index was weaker by 0.09%, while Japan's Nikkei index closed down 1.1%.

(Reporting by Winni Zhou and Andrew Galbraith; Editing by Devika Syamnath)