The United States could see "astounding" coronavirus deaths in the coming months as infection rates soar in the colder months, said Dr. Scott Gottlieb told CNBC's "Closing Bell" on Friday.
According to data from the Covid Tracking Project, an independent volunteer organization launched by journalists in the Atlantic, there were 916 deaths from Covid-19 in the United States on Friday. New coronavirus cases dwarfed 71,600 on Thursday.
Gottlieb, a doctor who acted as agent for the U.S. Food and Drug Administration, stressed that doctors improved their treatment for Covid-19 patients during the pandemic and reduced the death rate. He said it could have been reduced by 50%.
Patient care has also been improved through drugs like Gildes Sciences' remdesivir, which became an FDA-cleared treatment for Covid-19 on Thursday, as well as the use of steroids like dexamethasone, Gottlieb said. President Donald Trump received both after his coronavirus diagnosis.
Despite these positive developments, Gottlieb said the challenge facing the US is how widespread the virus is across the country. "Mortality will decrease, but we will infect so many people that the daily death statistics will fluctuate," said Gottlieb, who headed the FDA from May 2017 to April 2019 under Trump.
In the coming weeks, "well over 1,000" new deaths could be reported each day, he said. "And we could retest some of the totals we saw back in the spring when we reported 2,000 deaths a day from this virus, just because of the sheer number of people we're likely to infect in winter."
Nearly 8.5 million cases of Covid-19 have been confirmed in the United States, and at least 223,752 people have died, according to Johns Hopkins University.
Public health experts have been warning for months that colder weather in fall and winter is likely to coincide with a coronavirus resurgence, as people spend more time indoors, where transmission can more easily occur.
The pandemic is worsening in countries around the world, and some nations are on a "dangerous path," the World Health Organization head warned on Friday. "We are at a critical point in this pandemic, especially in the northern hemisphere," said Director General Tedros Adhanom Ghebreyesus.
Restrictions have been reintroduced in parts of Europe, including an overnight curfew in regions of France to reduce the spread of Covid-19.
Gottlieb said he believes the U.S. response to rising infection rates will be targeted intervention in hot-spot areas, rather than the lockdown orders issued in the early stages of the pandemic when inadequate testing made it difficult to determine where the transmission occurred.
"I think we're going to endure a lot more infections … and the healthcare system is going to have to bear the brunt of that burden because I don't think you have the popular will to stick with. Homework or extensive mitigation," he said.
"If everyone just wore masks, it would reduce the spread," he added.
– CNBC's Noah Higgins-Dunn contributed to this report.