Covid cases are rising in all 50 US states as the now-dominant Delta variant tears across the country, with President Joe Biden warning it has now become a “pandemic of the unvaccinated”.

Federal health officials sounded the alarm yesterday about a surge in infections fuelled by the twin threats posed by the highly transmissible variant and a stagnation in efforts to vaccinate Americans.

Rochelle Walensky, director of the Centers for Disease Control and Prevention (CDC), said the US was seeing an average of 26,000 new coronavirus cases a day – a seven-day average that is 70 per cent higher than last week.

Mr Biden missed his target of 70 per cent of adults vaccinated by July 4 US Independence Day, in large part because of the hesitance of young people to get the jab.

US First Lady Jill Biden looks on as Alfred Lee Smith (C) is vaccinated with the Johnson & Johnson COVID-19 vaccination at a facility at Alfred E. Beach High School in Savannah, Georgia

Credit: AFP

The rising numbers are being driven by large pockets of infection among the more than 90 million eligible Americans who have yet to get shots. Just four states with low vaccination rates made up 40 per cent of new cases last week, and nearly half of them came from Florida alone.

In recent days, the administration has turned its focus to younger Americans. It enlisted pop star and Tik Toker Olivia Rodrigo for a White House visit with Mr Biden and top infectious disease expert Dr Anthony Fauci.

Hospitalisations and deaths are also seeing increases – about 36 per cent and 26 per cent, respectively, with Ms Walensky noting this was another “critical moment” in the outbreak.

More than 99 per cent of deaths and 97 per cent of hospitalisations are among people who have not been vaccinated, according to the CDC.

In an unprecedented attack on Big Tech, the US president hit out at social media platforms like Facebook for “killing people” by allowing disinformation about the vaccine to spread online.

“Look, the only pandemic we have is among the unvaccinated, and that — and they’re killing people,” Mr Biden told reporters.

As the prevalence of infection grows, some authorities have begun to impose renewed restrictions.

Los Angeles from Saturday night will return to mandatory mask-wearing indoors, even for people who have been vaccinated, as the nation’s largest county seeks to contain a sustained increase in cases among its 10 million population.