The new coronavirus variant is a genuine cause for unease. Omicron appears to be highly transmissible, and it will most likely swamp the world in the months ahead. It is too early to know whether it will be more virulent than the delta variant or more evasive of vaccine immunity. But it is not too early to decide what to do about it. The tools to respond exist, if we will only be serious about wearing masks and getting vaccinated.

Even with the unknowns, vaccines work. They can protect against the delta variant raging everywhere. Boosters create a high level of immunity against delta and may help fend off omicron, too. The vaccines are a lifesaver to people who might otherwise die. Why hesitate to get vaccinated, refuse to wear a mask or deride mandates for both at this stage of the pandemic? Why is a quarter of the U.S. population without at least one vaccine dose — essentially driving at high speed without a seat belt? How many more of the unvaccinated will be hospitalized, intubated and die? Anyone in the United States who can easily get a free vaccine and refuses to do so is leaving themselves vulnerable to a killer disease that has already taken more lives than were lost in the line of duty during the Civil War.

Why should anyone become another victim?

Vaccines have already shown to be tremendously effective, bringing infection levels way down from last winter’s surge. But delta is still tormenting the unvaccinated and, with the arrival of the holidays, appears to be surging anew. Ominous reports have been coming in recent weeks from Minnesota, Michigan, Colorado, Vermont, Nebraska and New Hampshire. New York state just reported the most new cases since January — 56 hospitals in the state had a bed capacity of 10 percent or less. Massachusetts reported its largest single-day case count since last winter’s surge. Nirav Shah, director of the Maine Center for Disease Control and Prevention, told the Associated Press, “Omicron is a spark that’s on the horizon. Delta variant is the fire that’s here today.”

President Biden’s latest pandemic strategy, promising to fight the pandemic with “science and speed,” calls for more testing, better access to vaccines, tighter travel restrictions and other measures. These are all pointing in the right direction, but the ambition is modest. For example, Mr. Biden proposes that private health insurers reimburse people for rapid at-home tests, not just those obtained at a doctor’s office or pharmacy. That might help, but at-home diagnostic tests are still not being manufactured rapidly enough so that the whole country can feel comfortable using them regularly and without cost.

Masks and other simple mitigation techniques are going to be vital again this winter. We know what to do to fight this war. Governments, businesses, schools and other institutions play a big role, but it is ultimately up to individuals to regard the virus for what it is: potentially life-threatening. The way to survive is at hand. Grab it.