By Andrea Shalal and Carl O’Donnell

WASHINGTON (Reuters) – The White House on Thursday said it would send out special teams to hot spots around the United States to combat the highly contagious Delta coronavirus variant, and urgently called on Americans who have not been vaccinated to get shots.

White House COVID-19 senior adviser Jeffrey Zients told reporters the “surge response” teams would be ready to speed additional testing supplies and therapeutics to communities that were experiencing increases in COVID-19 cases.

The seven-day-average number of COVID-19 cases in the United States has risen 10% since last week, U.S. Centers for Disease Control and Prevention Director (CDC) Rochelle Walensky said on a Tuesday press call.

The more easily transmitted Delta variant, which was first detected in India, is thought to have become the second most prevalent coronavirus variant in the United States, she added.

“It is clear that communities where people remain unvaccinated are communities that remain vulnerable,” Walensky said, adding that 1,000 counties in the United States have vaccination rates below 30%.

Zients said federal personnel will assist communities with public health staffing and the CDC will provide assistance in containing potential outbreaks.

The United States remains a world leader in COVID-19 vaccinations, with more than 180 million Americans having received at least one shot.

(Reporting by Lisa Lambert, Carl O’Donnell and Andrea Shalal; Editing by Jonathan Oatis and Bill Berkrot)