'The war has changed': US documents sound alarm on Delta Covid variant

US CDC calls for better communications to halt spread; even those vaccinated should wear masks, says CDC

The "war has changed" against COVID-19 because the Delta variant is as contagious as chickenpox, can be passed on by vaccinated people and may cause more serious disease than earlier strains, according to the U.S. Centers for Disease Control (CDC).

An internal CDC document, titled "Improving communications around vaccine breakthrough and vaccine effectiveness", said the fast-spreading variant required a new approach to help the public understand the danger.

It said the unvaccinated were three times more likely to become infected and more than 10 times more likely to become seriously ill or die, it said.

"Acknowledge the war has changed," it said. "Improve