When will regulators rule on safety and efficacy?

Trial will recruit 60,000 across three continents

World round-up: China reports new infections as Greece announces record daily number of cases

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Results published in Lancet suggest vaccine stimulates the production of antibodies

Scale of scientific endeavour is unprecedented with more than 145 candidates in development

Cautious optimism that vaccine may be ready next year

Experimental trials will involve 360 patients in two age groups in bid to fast-track vaccine