Swiftly rising coronavirus cases across the US and abroad have fuelled fears of a pandemic resurgence and sent shockwaves through stock markets as the highly contagious Delta variant appears to be taking hold.

Many of the new outbreaks are in parts of the country where Covid-19 vaccinations have lagged, prompting political leaders to ramp up pressure on reluctant Americans to get the inoculations.

President Joe Biden, citing higher rates of Covid-19 in states with low vaccination rates, said during a speech that the nation's economic recovery hinged on getting better at controlling the pandemic.

"So please, please get vaccinated," Biden pleaded. "Get vaccinated now."

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