• Coronavirus cases in the U.S. will increase due to the delta variant, Dr. Scott Gottlieb told CNBC on Wednesday.
• However, he stressed, "I don't think it's going to be a raging epidemic across the country like we saw last winter."
• Parts of the country with high vaccination rates such as the Northeast should be "largely protected," the former FDA chief said.
• However, he cautioned, "I don't think we should be cavalier about this."

Dr. Scott Gottlieb told CNBC on Wednesday he believes there's enough Covid immunity protection across the U.S. population that, even as the highly transmissible delta variant circulates, the country is unlikely to experience a situation nearly as dire as previous points in the pandemic.

"I don't think it's going to be a raging epidemic across the country like we saw last winter. I think that there's going to be pockets of spread, and prevalence overall is going to pick up," the former Food and Drug Administration commissioner said on "Squawk Box." 

"But I think in parts of the country where vaccination rates are high, and that's certainly true in the Northeast, I think we're largely protected — at least from the current variants that are circulating," added Gottlieb, who serves on the board of Covid vaccine maker Pfizer.

On the other hand, Gottlieb said parts of the country are more vulnerable to outbreaks involving the Covid delta variant. Those are places where the number of people who have previously been infected or received the vaccine are low. He noted the situation in Missouri, where health officials have expressed concern about a rise in cases and hospitalizations, particularly in areas with lagging vaccination rates.

"If you're someone even who has been vaccinated living in those parts of the country, and there's a dense epidemic of this new delta variant, you're at risk as well because we know the vaccines aren't 100% and we know in vulnerable populations — people who are immunocompromised, people who are much older — the vaccines may not work as well over time."

The delta variant, first found in India, has been identified in more than 90 countries, including the U.S, where about every two weeks its prevalence is doubling. In some countries, such as Israel, concern over the delta variant have led to governments to tighten public health restrictions.

The U.K. earlier this month pushed back the latest phase of its economic reopening, citing the pace of new delta variant infections and an increase in hospitalizations. The majority of cases have been in unvaccinated people.  

Officials in Los Angeles County this week issued indoor mask guidance, including for fully vaccinated people, due to worries over the delta variant. It comes about two weeks after the county joined the state of California in lifting indoor mask mandates for fully vaccinated people in most settings.

The World Health Organization on Friday also urged fully vaccinated people to keep wearing face masks, with officials saying there's a need to "play it safe" because many parts of the globe remain unvaccinated.

"The goal should be to try to reduce transmission as much as possible here in the United States. I don't think we should be cavalier about this," said Gottlieb, who led the FDA from 2017 to 2019 in the Trump administration. "But we're going to see the overall impact of the virus be substantially reduced because so many people have become vaccinated."

In the U.S., roughly 154.2 million people, or 46.4% of its population, has been fully vaccinated, according to data from the Centers for Disease Control and Prevention. Nearly 180 million individuals, or 54.2% of the country's population, have received at least one dose.

The U.S. is averaging around 12,400 new coronavirus cases per day, based on a seven-day average, according to a CNBC analysis of Johns Hopkins University data. That's up 10% compared with one week ago. The daily average of deaths from Covid is down 7% over that same period, to 278 per day.

Despite the increase in cases, Gottlieb said he believes public health officials in the U.S. should be cautious about reimplementing pandemic restrictions at the moment. Daily new infections remain dramatically lower than their single-day peak in the U.S. of 300,462 on Jan. 2, according to Johns Hopkins data.

"I think the right response, first and foremost, is to get more people vaccinated," Gottlieb said. "We're at a point right now where our mitigation really should be reactive, not proactive," he added. "We shouldn't be shutting things down or putting in mask mandates in anticipation of spread. I think we should do it when we see signs of spread, signs of outbreaks."

Disclosure: Scott Gottlieb is a CNBC contributor and is a member of the boards of Pfizer, genetic testing start-up Tempus, health-care tech company Aetion Inc. and biotech company Illumina. He also serves as co-chair of Norwegian Cruise Line Holdings' and Royal Caribbean's "Healthy Sail Panel."