Nov 27 (Reuters) - Foreign investors remained net buyers of Japanese equities for a third straight week that ended Nov. 20, buoyed by progress in a second coronavirus vaccine-related developments that rekindled hopes of a swift global economic recovery.

Overseas investors were net buyers of stocks worth 597.17 billion yen ($5.74 billion) last week, after purchasing over 1 trillion yen in each of the previous two weeks, data from Japanese exchanges showed.

They bought 333.18 billion yen in cash equities markets and 263.99 billion yen worth of derivatives.

Moderna Inc said its experimental COVID-19 vaccine was 94.5% effective in preventing infection based on interim late-state data, which spurred investor sentiment last week.

The optimism, however, faded partially as Tokyo raised its coronavirus alert to the highest level latter last week due to a sharp increase in coronavirus cases.

The Topix index rose 1.4% while the Nikkei share average added 0.6% last week, both marking a third straight week of gains.

Meanwhile, Japanese investors sold overseas equities worth 1.43 trillion yen last week, marking their biggest weekly net selling since mid-July, finance ministry data showed. ($1 = 104.0300 yen)

(Reporting by Gaurav Dogra and Patturaja Murugaboopathy; Editing by Rashmi Aich)