• Almost no one who has been vaccinated is being sent to the hospital or dying from the coronavirus, White House officials said.
• The remarks came as President Joe Biden's Covid team focuses on the portion of the population that has not been inoculated against the virus.
• The continued push for vaccinations is now competing with the rise of the highly transmissible delta variant in the U.S.

As more people get vaccinated against Covid-19 in the U.S., a vast majority of hospitalizations and deaths are occurring among people who haven't yet gotten a Covid shot, White House officials said Thursday.

"Virtually all Covid-19 hospitalizations and deaths in United States are now occurring among unvaccinated individuals," White House coronavirus response coordinator Jeff Zients said at a press briefing. He said cases will continue to rise, especially among unvaccinated people, particularly as the delta variant takes hold in the U.S.

Rochelle Walensky, director of the Centers for Disease Control and Prevention, said the Covid vaccines currently being used are proving to be successful in preventing severe disease, hospitalization and death from the delta variant.

Cases are still going up: The seven-day moving average of new cases rose to 13,900 per day, an 11% increase over the previous week, Walensky said.

But recent data show that "the vaccines indeed are effective against" the delta variant, White House chief medical advisor Dr. Anthony Fauci said in the briefing.

"The bottom line is there's simply no reason that anyone 12 and older should be severely impacted by this virus," Zients said.

Federal officials are increasingly seeing outbreaks in communities with low immunization rates, they said.

Walensky said the delta variant now accounts for roughly 80% of all new cases in parts of the Midwest and upper mountain states, according to early CDC data.

"This rapid rise is troubling. We know that the delta variant has increased transmissibility and it is currently surging in pockets of the country with low vaccination rates," Walensky said at the briefing.

The remarks came as President Joe Biden's Covid team focuses on the portion of the population that hasn't been inoculated yet.

Millions of people in the U.S. remain unvaccinated, "and because of that, their communities are at risk, their friends are at risk, the people they care about are at risk," Biden said Tuesday. He said the administration is focusing more on boosting vaccination availability in places such as doctor's offices and work settings, while also expanding door-to-door outreach efforts.

The delta variant, which was first detected in India, has now spread to more than 100 countries, including the U.S., according to the World Health Organization.

The highly transmissible variant is likely to have a lingering impact around the world for the foreseeable future, scientists predict.

Olympics organizers announced Thursday they are banning all spectators from the games this year in Japan, which just declared a new Covid-related state of emergency in Tokyo, in part due to the delta variant.

Nearly 158 million people in the U.S. are fully vaccinated — about 48% of the population, according to CDC data. Just over 67% of Americans ages 18 and up have received at least one dose.

— CNBC's Berkeley Lovelace Jr. contributed to this report.