CNBC's Meg Tirrell joins 'Squawk Box' to report on the U.S.'s surge in reported Covid-19 cases, which are up more than 200% in the last two weeks alone. For access to live and exclusive video from CNBC subscribe to CNBC PRO: https://cnb.cx/2NGeIvi  U.S. Covid cases have hit their highest level of the pandemic as two highly infectious variants circulate throughout the country and health officials urge Americans to get vaccinated and boosted against the virus. Nationwide daily new cases were at a record seven-day average of more than 265,000 as of Tuesday, according to data compiled by Johns Hopkins University, surpassing the previous high mark of about 252,000 average daily cases set on Jan. 11, 2021. The fresh pandemic peak comes as the delta and omicron variants are spreading simultaneously. The previously dominant delta variant was already driving U.S. case counts higher this fall before the emergence of omicron, which is contributing to a near-vertical rise in daily new cases. About 75,000 Americans are hospitalized with Covid-19 and the country is reporting more than 1,500 daily deaths. Though both figures are rising, they are lower than when the last daily case record was set nearly a year ago, before Covid vaccinations were widely available. Hospitalizations topped 137,000 at that point, according to a seven-day average of data from the Department of Health and Human Services, and Johns Hopkins data shows the average death toll was more than 3,200 per day. Roughly 62% of the U.S. population is fully vaccinated with two doses of the Pfizer or Moderna shots or one dose of the Johnson & Johnson vaccine as of Tuesday, according to the Centers for Disease Control and Prevention. U.S. health officials have warned that the risk remains highest for the unvaccinated and are pushing Americans to get a booster dose to better protect themselves against omicron. “It’s got over 50 mutations, and because of those mutations just being vaccinated with two doses may not be enough,” CDC Director Dr. Rochelle Walensky told CNBC’s “The News with Shepard Smith” last week. “And so we really do need people to get boosted in order to increase their protection, especially against severe disease and death with omicron.” In the United States, omicron represented 59% of sequenced Covid cases while delta represented 41% last week, according to CDC estimates. While the global scientific community is still gathering data on the new variant, which was first detected in southern Africa in late November, there has been some encouraging early news. Real-world studies from South Africa and the United Kingdom suggest that people infected with omicron develop more mild illness compared with delta, and Pfizer and Moderna have each said that a third dose of their mRNA Covid vaccines appears to provide significant protection against omicron, though a two-shot regimen has been found to be less effective against infection. A more mild disease with greater transmissibility could still wreak havoc on health-care systems if the absolute number of cases gets high enough, experts say. That’s because even if a smaller share of people infected end up going to the hospital, that smaller share of a very large number could be enough to strain hospitals and impact care for both Covid and non-Covid patients. “A higher peak can further overwhelm the system for other people as well,” said Dr. Bruce Y. Lee, a professor of health policy and management at the City University of New York School of Public Health, explaining that fuller hospitals would make it harder to treat those with heart attacks or cancer or who, for example, got into a car accident. The White House will deploy 1,000 military medical personnel to support hospitals facing a surge of patients infected with Covid this winter, President Joe Biden announced last week. The government will also purchase 500 million at-home tests that Americans can order online for free with delivery beginning in January. » Subscribe to CNBC TV: https://cnb.cx/SubscribeCNBCtelevision » Subscribe to CNBC: https://cnb.cx/SubscribeCNBC Turn to CNBC TV for the latest stock market news and analysis. From market futures to live price updates CNBC is the leader in business news worldwide. The News with Shepard Smith is CNBC’s daily news podcast providing deep, non-partisan coverage and perspective on the day’s most important stories. Available to listen by 8:30pm ET / 5:30pm PT daily beginning September 30: https://www.cnbc.com/2020/09/29/the-news-with-shepard-smith-podcast.html?__source=youtube%7Cshepsmith%7Cpodcast    Connect with CNBC News Online Get the latest news: http://www.cnbc.com/ Follow CNBC on LinkedIn: https://cnb.cx/LinkedInCNBC Follow CNBC News on Facebook: https://cnb.cx/LikeCNBC Follow CNBC News on Twitter: https://cnb.cx/FollowCNBC Follow CNBC News on Instagram: https://cnb.cx/InstagramCNBC https://www.cnbc.com/select/best-credit-cards/  #CNBC #CNBCTV