FACTBOX-Latest on the worldwide spread of coronavirus

AMERICAS * U.S. President Donald Trump called for a big stimulus to cushion the economic impact of COVID-19, as the country's tally of infections surpassed eight million while reporting record spikes in several states.

The European Medicines Agency could approve three COVID-19 vaccines early next year, while Pfizer plans to apply for U.S. emergency use of its vaccine candidate as early as November.

DEATHS AND INFECTIONS * For an interactive graphic tracking the global spread of COVID-19, open https://graphics.reuters.com/world-coronavirus-tracker-and-maps/ in an external browser.

* Eikon users, see MacroVitals for a case tracker and summary of the news. EUROPE

* EU leaders agreed to hold video conferences almost on a weekly basis to coordinate national measures against the pandemic. * The Kremlin said it was worried by the record surge in Russia's COVID-19 cases, but that the situation was still under control.

* Switzerland signed a contract for up to 5.3 million doses of a potential COVID-19 vaccine being developed and tested by AstraZeneca and Oxford University. * Serbia ordered the mandatory wearing of masks at all times outside the home and introduced other measures to deal with the spread of coronavirus.

* The Czech healthcare system faces a difficult few weeks ahead but is not threatened by collapse, health officials said after another daily record in new cases. AMERICAS

* U.S. President Donald Trump called for a big stimulus to cushion the economic impact of COVID-19, as the country's tally of infections surpassed eight million while reporting record spikes in several states. * Democratic presidential candidate Joe Biden tested negative for COVID-19 after he flew earlier this week with a person who subsequently tested positive.

* Mexico's death toll surpassed 85,000 after it reported 387 additional fatalities along with 5,514 new cases. ASIA-PACIFIC

* Japan's prime minister vowed to do "whatever it takes" to organize the Tokyo Olympics next year. * The Philippines' coronavirus task force has lifted a ban on overseas travel for Filipino tourists.

* Hundreds of New Zealand plane passengers started arriving in Sydney as part of a new trans-Tasman travel bubble amid a rapidly falling growth rate in cases at the epicenter of Australia's coronavirus outbreak. MIDDLE EAST AND AFRICA

* South Africa will embark on massive public works and job-creation drive in response to the crisis, President Cyril Ramaphosa said, unveiling a plan to return Africa's most industrialized economy to growth. MEDICAL DEVELOPMENTS

* "Human challenge" trials of potential vaccines, where volunteers are deliberately infected with the disease, could become a reality after a British biotech firm said it was in advanced talks with the government to create and provide strains of the virus. * A WHO trial that concluded Gilead Sciences Inc's remdesivir did not significantly help COVID-19 patients is reliable, a scientist who evaluated the data said, as the U.S. company criticized its methodology.

* Spanish pharmaceutical company PharmaMar said a clinical trial of its cancer drug Aplidin to treat adult patients with COVID-19 was successful and it now aims to start phase III trials. ECONOMIC IMPACT

* Financial markets remained shaky as hopes for a new round of U.S. fiscal stimulus met fears that social restrictions to tackle the pandemic would undermine the economic recovery. * Oil prices were dragged down by concerns that a spike in COVID-19 cases in Europe and the United States is curtailing demand in the regions, while a stronger U.S. dollar also added to the pressure.

* Japan's finance minister brushed aside some ruling party lawmakers' calls for a big extra stimulus budget, saying the situation was different from earlier this year.