Biden administration intelligence officials are privately warning about a potentially gigantic influx of migrants at the U.S.-Mexico border this spring — with possibly 170,000+ people prepared to cross if COVID policies are ended, Axios' Jonathan Swan and Stef Kight report.

• Why it matters: Border officials have used COVID rules more than 1 million times to turn away migrants from the southern border. Senior Biden officials expect the policies to end, but don't know for sure.

Behind the scenes: Internal discussions have raised alarms that human trafficking networks throughout Mexico and Central America will exploit the situation to "generate a mass migration event."

• Top Biden officials representing multiple agencies have been meeting to discuss a whole-of-government plan to deal with the potentially record-breaking spring influx of migrants.

DHS has branded it the "Southwest Border Mass Irregular Migration Contingency Plan."

• 💡 The plan is sweeping, reflecting how serious the Biden administration believes the situation could soon become, worsening a border surge that has troubled it from the beginning.

👀 What we're watching: The response includes a newly created — and previously unreported "Southwest Border Coordination Center (SBCC)" — essentially a war room to coordinate an interagency response.

• The center will physically operate out of the DHS headquarters at the old St. Elizabeths Hospital in D.C.

Department of Homeland Security intelligence estimates warn that perhaps 25,000 migrants are already in Mexican shelters just south of the border, waiting for COVID policies, under Title 42, to end.

• Yesterday, DHS Deputy Secretary John Tien asked employees "to consider stepping forward to support the DHS Volunteer Force," citing large numbers of migrants at the southwest border, according to an email seen by Axios.
• The email seeks general support for U.S. Customs and Border Protection and help with data entry.

White House spokesperson Vedant Patel didn't confirm or dispute specifics of Axios' reporting but said in a statement: "Of course the Administration is doing our due diligence to prepare for potential changes at the border."

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If this migrant influx materializes, the Department of Homeland Security could request aircraft from the U.S. Marshals Service to help transfer migrants to other areas of the border, Axios' Stef Kight and Jonathan Swan report.

• DHS also could call on additional air and ground transportation from the Department of Defense.

Officials could request dozens of buses from the Bureau of Prisons to transport migrants between DHS facilities.

• And they expect to expand and even build new soft-sided facilities that can shelter up to 2,000 migrants apiece.
• In addition to preparations on the U.S. side of the border, officials are also planning how to coordinate with Mexico and other Latin American nations.

The backdrop: Border resources are already strained, with unusually high numbers of people attempting to cross every month for a year straight.

• Officials expect those numbers to climb even higher in coming months due both to seasonal trends and the expected end of Title 42 policies.

The backstory: The CDC's Title 42 order, first issued under then-President Trump in March of 2020, uses the pandemic as a reason for expelling migrants attempting to enter the U.S.

• Despite outcry from progressive Democrats and immigration advocates, the Biden administration has continued to rely on the policy to turn back migrant families and single adults.

What's next: The administration is leaning toward ending Title 42 expulsions, Reuters reported last week.

• CDC reassesses the Title 42 order every 60 days. The next deadline for renewal is in early April. "We continue to defer to the CDC on the use of Title 42 and how long it might remain in effect," a White House official told Axios.

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The issue of immigration has plagued President Biden since he took office, opening him up to criticism from both the right and the left.

• Democrats have been most critical of the continued use of Title 42, which they see as a cruel Trump-era policy.
• Republicans have pointed to record numbers at the border, and reports of migrants being released into the U.S. by overwhelmed officials.

By the numbers: After declining in January, the number of encounters with migrants at the border ticked up in February to 165,000, according to data released Tuesday.

• Border patrol arrests reached an all-time high in fiscal year 2021, at nearly 1.7 million.

Officials are projecting similar numbers for this fiscal year with the end of Title 42, according to sources familiar with the estimates.

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These two satellite photos show war damage to apartment buildings and a church in Sumy, in northeastern Ukraine.

⚡ Breaking: Hundreds of civilians, who were sheltering in a theater, are feared trapped after the building was smashed by a Russian airstrike in the besieged Ukrainian city of Mariupol, AP reports.

• The pavement in front of, and behind, the once-elegant theater was marked with huge white letters spelling out "CHILDREN" in Russian, according to images released by the Maxar space technology company.

Pfizer says at least some Americans will soon need a fourth shot of its coronavirus vaccine, Axios' Caitlin Owens writes.

• Why it matters: If it's true the third shot's ability to ward off severe disease drops after a few months, that may suggest Americans need a better booster.

The catch: Regulators want to see more data before they're convinced another booster is necessary.

Pfizer announced Tuesday that it will submit a request to the FDA for a fourth dose of its COVID vaccine to be authorized for people 65 and older.

• Pfizer CEO Albert Bourla said Sunday on CBS News' "Face the Nation": "We know that the duration of the protection doesn't last very long. ... Right now, the way that we have seen, it is necessary — a fourth booster right now."

The other side: Cornell virologist John Moore said giving seniors another dose is easier to justify than authorizing additional shots for the entire population.

💭 What Dr. Fauci says: Officials will be paying close attention to effectiveness against hospitalization over time, Fauci said in an interview.

• "We obviously need to continue to work on the durability of protection, either by a boosting regimen … and/or perhaps using different platforms of vaccines that give a greater durability," Fauci added. "These are all things that are just under consideration."

The bottom line: Administering booster shots every six months or so isn't a great long-term public health strategy, particularly if it's done with the goal of preventing mild illnesses, experts say.

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This image from NASA shows star 2MASS J17554042+6551277, which was used to align the 18 mirrors of the James Webb Space Telescope, with galaxies and stars photobombing behind it.

• A red filter was used, and the hexagonal shape of Webb's mirrors made the shimmering star look more spiky.

Scientists were giddy as they watched the test photos arrive, AP reports:

• This image is of a star 100 times fainter than the human eye can see — 2,000 light-years away. A light-year is nearly 6 trillion miles.

"You can't help but see those thousands of galaxies behind it — really gorgeous," said Jane Rigby, Webb operations project scientist.

• Those galaxies are several billions of years old. Eventually, scientists hope Webb will see so far away and back in time that it will only be "a couple hundred million years after the Big Bang," she said.

Watch a NASA video.

Former Homeland Security Secretary Jeh Johnson is marshaling support for Supreme Court nominee Ketanji Brown Jackson on what's expected to be a top issue at her confirmation hearings, which begin Monday:

• As a public defender, and later in private practice, she represented several Guantanamo Bay detainees between 2005 and 2009.

"[T]he American system of justice depends upon strong advocacy on both sides of the courtroom," says a letter from Johnson and other key Obama-era national-security lawyers.

• A final confirmation vote is expected in early April.

Read the full letter.

In Edinburgh, Scotland, 2-year-old Innes Boyd and 5-year-old Lenny Boyd soak in Van Gogh Alive — an immersive, multi-sensory art experience, combining high-definition projections of Van Gogh's paintings with digital surround-sound and aromas of Provence. 

• "The masterpieces come to life, giving visitors the sensation of walking right into his paintings." Go deeper.