What you need to know about the coronavirus right now

Sept 22 (Reuters) - Here's what you need to know about the coronavirus right now:

Biden pledges new vaccine donations

President Joe Biden will push world leaders on Wednesday to do more to curb the pandemic, and announce a U.S. pledge to buy 500 million more vaccine doses to donate to other countries.

Holding a virtual summit to boost global vaccination rates, Biden hopes to show he is leading by example with the pledge, which will bring U.S. donations to the rest of the world up to more than 1.1 billion doses.

The vaccines from Pfizer and BioNTech will be made in the United States and shipped to low and lower middle-income countries starting in January, a U.S. senior administration official said ahead of the announcement.

Northern Chinese city in semi-shutdown

China's northeastern city of Harbin, population 10 million, went into semi-shutdown after reporting new locally transmitted COVID-19 cases for the first time since early February.

Three of 16 new local cases reported in China for Sept. 21 were in Harbin, the provincial capital of Heilongjiang, the National Health Commission said on Wednesday. The last reported locally transmitted cases in the city were on Feb. 4.

Harbin on Wednesday vowed to complete an initial round of city-wide testing by Thursday, and told its residents to refrain from stepping outside their homes, unless necessary, before their test results are out.

Melbourne police arrest 200 at lockdown protests

Police in Australia's second largest city of Melbourne arrested more than 200 people after projectiles thrown by protesters injured two officers on Wednesday, the third consecutive day of demonstrations against COVID-19 curbs.

New Zealand may not get back to having zero coronavirus cases in the community, the director general of health said on Thursday, as the country continues efforts to stamp out the infectious Delta variant of the virus.

Thailand to accelerate vaccinations

Thailand will speed up vaccinations and introduce urgent stimulus measures to mitigate the impact of its most severe coronavirus outbreak, its prime minister said on Wednesday.

Thailand has reported more than 1.5 million infections and 15,000 deaths, about 99% of those since April this year, after a year of successful containment during which its key tourism sector collapsed.

The country has pushed back plans to re-open Bangkok and some other major cities to foreign arrivals until November, due to vaccination rates falling short of targets, a senior official said on Wednesday.

Canada's Alberta replaces health minister as COVID-19 rages

The premier of Canada's Alberta province replaced his health minister in a cabinet reshuffle on Tuesday, as a fourth wave of cases swamped the healthcare system and the government came under fire for mishandling the pandemic.

Hospitals in Canada's western oil-producing province are buckling under a record number of cases driven by the Delta variant. Intensive care units are 87% full, even with extra "surge beds" added, and Alberta has canceled elective surgeries and discussed transferring patients to other provinces.

Germany won't pay unvaccinated workers in quarantine

German health authorities are planning new rules under which unvaccinated workers would not receive compensation for lost pay if coronavirus measures forced them to quarantine, according to a draft decision by state health ministries.

The rules would come into force from Oct. 11 at the latest, a draft document seen by Reuters showed.

China's Clover says its vaccine candidate 67% effective

A potential vaccine from China's Clover Biopharmaceuticals was 67% effective against COVID-19 and 79% against the Delta variant in a large, late-stage trial, the company said on Wednesday.

(Compiled by Linda Noakes Editing by Bernadette Baum)