WASHINGTON: The United States on Thursday authorized an extra dose of Covid vaccine for people with weakened immune systems, as the country struggles to thwart the Delta variant.

"The country has entered yet another wave of the Covid-19 pandemic, and the FDA is especially cognizant that immunocompromised people are particularly at risk for severe disease," said acting Food and Drug Administration Commissioner Janet Woodcock in a statement.

France to offer Covid booster shots to elderly, vulnerable from September