Pfizer and BioNTech announced Tuesday that they have started clinical trials for a reformulated vaccine to protect against the Omicron coronavirus variant.

Why it matters: The rise of the Omicron variant has forced vaccine makers to reassess the effectiveness of their vaccines.

Two new Biden administration initiatives — mailing at-home COVID-19 tests to those who ask and making free N95 masks available — are hugely popular, each backed by 84% of Americans in the latest installment of the Axios/Ipsos Coronavirus Index.

Yes, but: Those who may need these most — the unvaccinated — are less likely to take advantage of the offerings, the survey found. And neither has boosted President Biden's numbers so far, meaning it's too little too late, or too soon to see a change.

Omicron infections are trending down nationally, but the number of deaths is as high now as it was during the summer's Delta wave.

Why it matters: Preventing death is the ultimate goal, and thousands of Americans continue to die from this coronavirus every day even though vaccines have been available to the public for roughly a year.

The FDA said Monday it's limiting the use of two monoclonal antibody therapies as COVID-19 treatments because data indicates they're "highly unlikely" to be effective against the dominant Omicron variant.

Driving the news: The FDA revised the authorizations for Regeneron and Eli Lilly "to limit their use to only when the patient is likely to have been infected with or exposed to a variant that is susceptible to these treatments," per a statement from the agency.

The New York State Department of Education (NYSED) issued a statement Monday telling schools to continue following Democratic Gov. Kathy Hochul's mask mandate after a state Supreme Court judge struck down the rule.

Why it matters: The agency pointed to a case in Albany County where a state Supreme Court judge denied a challenge from two school districts, ruling that Hochul and the state's health commissioner have the authority to enact a mask mandate in schools.

1. Health: Fauci: "Confident" Omicron cases will peak in February.
2. Vaccines: The shifting definition of fully vaccinated.
3. Politics: New York Supreme Court strikes down Gov. Hochul's mask mandate for public areas — Sarah Palin tests positive for COVID, delaying defamation trial — Virginia school boards sue Gov. Youngkin for lifting mask mandate.
4. World: U.K. to lift travel testing requirement for fully vaccinated — Beijing Olympic Committee lowers testing threshold ahead of Games.
5. Variant tracker

Former Alaska Gov. Sarah Palin (R) tested positive for COVID-19 on Monday, delaying the start of her defamation trial against the New York Times.

Why it matters: The trial will be closely watched, as it's a rare instance of a major media company defending its editorial practices before an American jury.

The British government said Monday that it will lift the COVID-19 testing requirement for fully vaccinated people arriving in England.

State of play: Those who are not fully vaccinated "will only need to take a pre-departure test and a PCR test on or before day 2 after arriving in England," British Transport Secretary Grant Shapps tweeted.

The definition of what it means to be "fully vaccinated" is evolving even as the CDC has remained careful not to change it officially.

Why it matters: CDC officials have been balancing the job of convincing Americans who've already gotten two doses of the importance of boosters with getting many Americans who still need their first doses to get their shots at all.

Gonzaga University suspended the season tickets of alumni John Stockton after the NBA Hall of Famer failed to comply with the school's basketball games mask mandate, the Spokesman-Review first reported.

Driving the news: "Basically, it came down to, they were asking me to wear a mask to the games and being a public figure, someone a little bit more visible, I stuck out in the crowd a little bit," the former Utah Jazz point guard told the outlet in an interview Saturday.