Covid-19 global updates: Two doses of Pfizer and AstraZeneca coronavirus vaccines effective against delta variant, study says

Here are some significant developments:

• China said Thursday that it will not accept the World Health Organization’s suggested plan for the second phase of investigation into the origins of the coronavirus. A senior Chinese health official criticized the agency’s proposal to include the lab-leak hypothesis as a research priority.
• Officials announced that some 200 million people or more than half of all adults in the European Union have now been fully vaccinated.
• The United States has extended restrictions on nonessential travel at the borders with Canada and Mexico until Aug. 21. The Department of Homeland Security said the decision was made because of the “continued transmission and spread of [the virus] within the United States and globally.”
• Australia’s most populous state Thursday reported its highest number of new, locally transmitted cases for the year, even as much of the country remained under lockdown to stem an outbreak of the more contagious delta variant. New South Wales, which includes Sydney, recorded 124 new infections, health authorities said.
• Tunisia’s president has ordered the military to oversee the country’s coronavirus response as the North African nation battles its worst outbreak of the pandemic. Earlier this week, the health minister was fired for bungling Tunisia’s vaccine rollout as the virus spread.
• The Tokyo 2020 Organizing Committee announced 12 new coronavirus cases among accreditation holders, including two unnamed athletes who were living in the Olympic Village. Eight athletes have tested positive since arriving in Tokyo for the Games.