July 22 (Reuters) - Copper prices advanced on Thursday, as investors appeared to shrug off worries over rising coronavirus cases worldwide and as China, the world's top metals consumer, decided to release less reserve metals than expected.

Three-month copper on the London Metal Exchange was up 0.4% at $9,381 a tonne, as of 0316 GMT, while the most-traded August copper contract on the Shanghai Futures Exchange increased 0.8% to 68,740 yuan ($10,632.14) a tonne.

Copper is often used as a gauge of global economic health.

China will sell another 30,000 tonnes of copper, 90,000 tonnes of aluminium, and 50,000 tonnes of zinc from its state reserves on July 29, less than the market has anticipated.

The auction marked the second sale by China this month as the government aims to rein in skyrocketing commodity prices.

Meanwhile, a new study found two doses of Pfizer or AstraZeneca's COVID-19 vaccine are nearly as effective against the highly transmissible Delta coronavirus variant, which has sparked concerns over economic recovery recently, as they are against the previously dominant Alpha variant.

FUNDAMENTALS

* ShFE lead climbed 1.1% to 15,935 yuan a tonne and LME lead advanced 0.3% to $2,344.50 a tonne, as German lead producer Berzelius Stolberg declared force majeure on metal shipments from its Stolberg smelter in Germany due to floods.

* The global world refined copper market showed a deficit of 75,000 tonnes in April, compared with 13,000 tonnes deficit in March, the International Copper Study Group said in its latest monthly bulletin.

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MARKETS NEWS

* Asian stocks rallied, bonds nursed losses and oil held onto sharp gains as investors seemed to set aside virus jitters for now and looked ahead to the European Central Bank for reassurance that policy support will continue for some time.

DATA/EVENTS (GMT)

0645 France Business Climate Mfg July

1145 EU ECB Refinance Rate July

1145 EU ECB Deposit Rate July

1230 US Initial Jobless Clm Weekly

1400 US Existing Home Sales June

1400 EU Consumer Confid. Flash July

($1 = 6.4653 yuan) (Reporting by Mai Nguyen in Hanoi, Editing by Sherry Jacob-Phillips)