As a summer wave of Covid-19 hits the US, questions about vaccines, quarantine and testing are back | CNN Covid-19 is on the rise again as the world approaches the fourth virus season since the coronavirus arrived on the scene. Amanda Musa CNN

Covid-19 is on the rise again as the world approaches the fourth virus season since the coronavirus arrived on the scene.

US Centers for Disease Control and Prevention data show a slight increase in hospital admissions, emergency department visits, and positive Covid-19 tests — although not nearly as high as in past summers.

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