The country's latest Covid surge could be a big one, and just in time for the holidays.

Multiple states have observed large jumps in cases this week — and in New York City, one of the first U.S. cities where the new omicron variant was detected earlier this month, the Covid positivity rate doubled in just three days. Schools like New York University and Cornell University cancelled in-person events and shifted finals online, and Broadway shows once again went dark.

The rest of the country is expected to follow suit in the coming weeks, as omicron joins or surpasses delta as the nation's dominant Covid variant. In New York and New Jersey, omicron already makes up roughly 13% of Covid cases, Centers for Disease Control and Prevention director Dr. Rochelle Walensky said in a White House briefing Wednesday.

Even sports leagues are being hit hard: Covid has sidelined more than 100 players and employees across the NFL, NBA and NHL this week. In the NFL alone, 75 players tested positive for Covid between Monday and Tuesday — an alarming number, considering that it took two weeks for a similar number to test positive in November.

The troubling spike is a harsh reminder: Covid remains a serious threat that could overwhelm the country's hospital systems again in the coming weeks and months.

Worried about what this means for you? Here's what you can do to protect yourself and others:

You can safely travel for the holidays — if you're vaccinated and (if eligible) boosted

First and foremost, vaccines and boosters can help prevent this wave from escalating.

"If we didn't have these tools, I would be telling you to really, really be worried," White House chief medical advisor Dr. Anthony Fauci said in a White House briefing Wednesday. "But we have tools."

You should still feel safe traveling and gathering for the holidays, Walensky noted, as long as everyone involved gets vaccinated and boosted once eligible.

Booster shots provide effective protection against all known Covid variants, including omicron. And notably, Fauci said, a booster dose can increase your protection against symptoms to 75% — so if you do get sick, you're much less likely to experience hospitalization or death.

On Tuesday, former White House senior pandemic advisor Andy Slavitt told CNN that businesses should mandate boosters before bringing people back into offices. The NFL recently mandated booster shots for large swaths of staffers, and some colleges are mandating boosters for students to return to campus in the spring.

Eventually, Fauci said, the definition of "fully vaccinated" will include boosters: "It's going to be a matter of when, not if."

Mask up, wash your hands and stay home when sick — even if you're asymptomatic

The omicron variant and recent surge in Covid cases don't really change the pandemic playbook, Walensky said: Wear masks in crowded indoor settings whether you're vaccinated or not, maintain good hand hygiene and stay home when you're sick.

Even if you're asymptomatic, stay home. If you test positive for Covid, you can easily transmit the dangerous virus to others — even if you feel completely fine.

It's all the more reason to get vaccinated and boosted, and encourage those around you to do the same.

"Continue to understand the importance for yourselves and your families and your community of getting vaccinated," Fauci said.

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