The US could soon see Covid-19 cases return to 200,000 a day, a level not seen since among the pandemic’s worst days in January and February, the director of the National Institutes of Health warned on Sunday.

While the US currently is seeing an average of about 129,000 new infections a day – a 700% increase from the beginning of July – that number could jump in the next couple weeks, Dr Francis Collins said on Fox News Sunday.

“I will be surprised if we don’t cross 200,000 cases a day in the next couple of weeks, and that’s heartbreaking considering we never thought we would be back in that space again,” Collins said.

Collins pleaded anew for unvaccinated Americans to get their shots, calling them “sitting ducks” for a Delta variant that is ravaging the country and showing little sign of letting up.