CNN  — 

More than 4 million doses of the coronavirus vaccine were reported administered in the past 24 hours, setting a new record and bringing the seven-day average to more than 3 million a day, the US Centers for Disease Control and Prevention reported Saturday.

Dr. Cyrus Shahpar, the Covid-19 data director at the White House, celebrated with a tweet early Saturday afternoon.

“Wow a record reporting day!! +4.08M doses reported administered over the total yesterday,” Shahpar wrote.

“First day w/ 4M or more. Also first time averaging more than 3M per day over the past week. Millions coming together to accelerate our progress toward controlling the pandemic!”

If people continue to wear masks, avoid crowds and let the vaccination program do its work, life will get back to normal in the US more quickly, said Dr. Anthony Fauci, President Joe Biden’s chief medical adviser on Covid-19.

“We are going to get to where (people) want to be, where I want to be, where you want to be – where we have enough people protected with the vaccines that we can go out and watch the cherry blossoms, and we can go out and enjoy as we get warmer weather,” Fauci told CNN’s Jim Acosta on Saturday. “It’s going to happen. It will.”

And once transmission rates fall far enough, the Centers for Disease Control and Prevention will issue revised guidelines about what fully vaccinated people can safely do, Fauci said.

“This is not going to last forever because every day you get 4 million, 3 million people vaccinated, you get closer and closer to control,” he said. “So what we are saying is double down. Just hang in there a bit longer, and the vaccine and the vaccinations in this country are going to override the surge in the virus. There’s no doubt the vaccine is going to win out.”

It has been nearly 109 days since the first Covid-19 vaccine shot was administered in the US, and 104 million people have since received at least one dose, the agency said. More than 59 million of them are fully vaccinated.

More than 161 million doses have been administered in the US, according to agency data published Saturday.

That’s 4,081,959 doses reported administered since Friday – a seven-day average of 3,072,527 doses per day. Data published by the CDC may be delayed, and doses may not have been given on the day reported.

With more than 30.6 million people having been infected with the virus and 554,522 people who have died of it, experts and officials are racing to get the population vaccinated before a possible fourth surge of cases.

Caution urged as CDC declares vaccinated people at low risk while traveling

In the continued move toward a sense of normalcy in the Covid-19 pandemic, the CDC announced Friday that fully vaccinated people can travel at low risk to themselves.

The agency said that as long as coronavirus precautions are taken, including mask wearing, fully vaccinated people can travel within the United States without first getting tested for Covid-19 or self-quarantining following trips.

“More and more you will start seeing the advantages of getting vaccinated,” Fauci said Saturday.

The CDC considers someone fully vaccinated two weeks after receiving the last required dose of the Covid-19 vaccine.

And though progress is being made with President Joe Biden saying Friday that a record 20 million vaccine doses were administered this week, health experts warn that more progress is needed before all Americans can consider the fight against the pandemic over.

The CDC still advises anyone who has not received the vaccine to avoid travel. Dr. Rochelle Walensky, director of the CDC, said she is still concerned about the pandemic and advises against non-essential travel altogether.

“I still continue to worry that with 80% of the population unvaccinated that we still have a lot of work to do to control this pandemic,” Walensky said.

On Friday, the Transportation Security Administration screened 1,580,785 people at airports, surpassing last Sunday’s record during the pandemic of 1.57 million travelers, according to the agency.

Friday was the 23rd straight day with more than 1 million air travelers, particularly during spring break.

The White House has been asking governors to stop rolling back mask mandates and to keep restrictions on crowd and gathering sizes.

“We say it over and over again that we need the local people. We need the governors and the mayors and others to say ‘We’re not out of it yet,’” Fauci said.

A traveler walks through Terminal 5 at John F. Kennedy International Airport in New York.

CDC updating guidance as science evolves

The US Centers for Disease Control and Prevention will continue to monitor Covid-19 data and update its travel guidance as the science evolves, Walensky said during a virtual White House briefing on Friday.

“The science on Covid-19 is constantly evolving. We will continue to monitor the evidence and provide updates as we learn more. With so many people still unvaccinated, it is important that everyone – regardless of vaccination status – continue to take prevention measures in public and adhere to our guidance on ways to reduce the spread of Covid-19,” Walensky said. “Wear a mask, socially distance, avoid crowds and poorly ventilated spaces, and wash your hands frequently.”

New guidance was also released Friday for cruise ship operators. The ships, which were early sites of the virus’ outbreaks, will have to operate practice cruises with volunteers before taking on paying customers, the CDC said.

Cruise ship operators will have to report coronavirus cases every day, instead of weekly, the CDC says in the new guidance. They also have to make vaccination of crew and port staff part of their plans.

You asked, we’re answering: Your top questions about Covid-19 and vaccines

States expand eligibility, fearing a surge

CNN medical analyst Leana Wen said she fears a fourth surge of the virus in the US as states lift precautions and variants continue to spread. And some state leaders share her concern.

“It’s clear that in Oregon, and across the country, the fourth surge of this virus is at our doorstep,” Oregon Gov. Kate Brown said. “While Oregon’s case numbers, fortunately, haven’t matched those of other states seeing large spikes, our numbers are rising.”

“I know we’re all fed up with a pandemic, physical distancing and mask wearing, but we are in the last few miles of the marathon,” Brown said.

And with cases rising in Vermont, the state’s Health Commissioner Dr. Mark Levine said he is “very concerned” that hospitalizations and deaths will follow.

With cases numbers increasing in West Virginia, the state expanded Covid-19 vaccine eligibility to all residents 16 and older, Gov. Jim Justice said Friday.

Alabama will also expand vaccine access to all 16 and older residents starting April 5, Gov. Kay Ivey said Friday.

“Truly, this vaccine is our ticket back to normal life. We are so close to getting Covid-19 in the rear view, and until then, we should all keep wearing our masks, get vaccinated and use the common sense the good Lord gave us,” the governor said in a press release.

Indeed, Fauci said Saturday that people need to continue wearing masks – even as more Americans are getting vaccinated – until the science shows otherwise.

Fauci, who also is director of the National Institute of Allergy and Infectious Diseases, said there are variables at play that make it difficult to say whether and when Americans will be able to relax on mask wearing.

“If we get a major surge and we have a continuation of an increase in cases, it is conceivable that we may be having to wear masks in 2022,” he told Fox News. “But if we continue to get people vaccinated, and we get the overwhelming majority of people together with those that have been infected and the level of infection goes way down, we very likely will not have to.”

Michigan spread may foreshadow what’s to come elsewhere

Michigan reported 8,413 new Covid-19 cases on Saturday, bringing the total to 692,206, according to the state health department. The reported case count is the highest the state has reported since December 7, 2020.

The current surge of coronavirus cases in Michigan and parts of Canada may foreshadow what’s to come elsewhere in the US as people move around more and a contagious viral variant spreads, one expert modeling the pandemic said Saturday.

Michigan reported 8,413 new Covid-19 cases on Saturday, bringing the total to 692,206, according to the state health department. The reported case count is the highest the state has reported since December 7, 2020.

Population health professor Ali Mokdad of the University of Washington’s Institute for Health Metrics and Evaluation (IHME) said the more easily transmitted B.1.1.7 variant first seen in Britain is fueling the spread, but so is people’s behavior.

“B.1.1.7 surge is unfolding in the northern states of the US and Canada. The rapid increases in cases seen in Michigan may be a marker of what may unfold in other parts of the US and Canada,” Mokdad said via Twitter.

“Cases and deaths are increasing in Europe despite extensive social distancing mandates, slowly increasing vaccination rates, and reduced mobility,” Mokdad tweeted.

On Thursday, the IHME upped its estimate of how many people are likely to die from coronavirus in the US by July 1 to 609,000 deaths, from 600,000 in last week’s forecast.

The spread of new variants may be in part to blame, but so is the relaxation of social distancing and mask mandates, the IHME said.

“Overly rapid reopening, well documented in the rapid increases in mobility in the US, increases the risk of an April/May surge despite rapid scale up of vaccination,” Mokdad tweeted.

“The trajectory of the pandemic requires stronger preventive measures and depends on the behavioral response in terms of vaccine confidence, mask wearing, and avoidance of situations that pose a high risk for transmission.”

2,600 cases of a rare condition in young children

Severe illness due to Covid-19 is still extremely rare among children, according to the American Academy of Pediatrics.

Even rarer is a condition associated with Covid-19 called MIS-C. More than 2,600 children have been diagnosed with the condition, according to new numbers that the CDC have been tracking since May.

Of those 2,617 cases, 33 children with MIS-C have died.

Symptoms typically include breathing trouble, stomach problems, heart problems, lesions in the mucous membranes (such as inside the mouth), skin problems and extreme inflammation.

The numbers of cases spiked in December but have started fall off as of March. Another 557 more cases have been reported since February 8.

Scientists still have a lot of questions as to why some children develop MIS-C after they’ve had, or been exposed, to Covid-19. MIS-C cases are tracked in 48 states, Puerto Rico and Washington DC. Additional cases are under investigation.

CNN’s Chris Boyette, Jen Christensen, Maggie Fox, Jacqueline Howard, Anjali Huynh, Chuck Johnston, Heather Law, Gregory Lemos, Lauren Mascarenhas, Deidre McPhillips and Maegan Vazquez contributed to this report.