Omicron Is Coming. The U.S. Must Act Now.

There’s very little we know for sure about Omicron, the Covid variant first detected in South Africa that has caused tremors of panic as winter approaches. That’s actually good news. Fast, honest work by South Africa has allowed the world to get on top of this variant even while clinical and epidemiological data is scarce.

So let’s get our act together now. Omicron, which early indicators suggest it could be more transmissible even than Delta and more likely to cause breakthrough infections, may arrive in the United States soon if it’s not here already.

A dynamic response requires tough containment measures to be modified quickly as evidence comes in, as well as rapid data collection to understand the scope of the threat.

Vaccine manufacturers should also immediately begin developing vaccines specifically for Omicron.

The United States, the European Union and many nations have already announced a travel ban on several African countries. Such restrictions can buy time, even if the variant has started to spread, but only if they are implemented in a smart way along with other measures, not as pandemic theatrics.

The travel ban from several southern African countries announced by President Biden on Friday exempts American citizens and permanent residents, other than requiring them to be tested. But containment needs to target the pathogen, not the passports.As a precaution, travel should be restricted for both foreign nationals and U.S. citizens from countries where the variant is known to be spreading more widely until we have more clarity.

We need stricter testing regimes involving multiple tests over time and even quarantine requirements for all travelers according to the incubation period determined by epidemiological data. We also need more intensive and widespread testing and tracing to cut off the spread of the variant. This means finally getting the sort of mass testing program that the United States has avoided and which has been part of successful responses to Covid in other countries.

If we aren’t willing to do all that, there is little point in a blanket ban on a few nationalities.

The reason we can even discuss such early, vigorous, responsible attacks on Omicron is because South African scientists and medical workers realized it was a danger within three weeks of its detection, and their government acted like a good global citizen by notifying the world. They should not be punished for their honest and impressive actions. The United States and other richer countries should provide them with resources to combat their own outbreak — it’s the least we can do.

The government should also be clear about when and by which benchmarks these restrictions will be modified. Travel bans can remain in place too long because they become more a matter of political signaling than public health.

Perhaps the best example of responding intelligently to an early warning is Taiwan.

Weeks before a prevaricating Chinese government finally acknowledged that the Covid virus was being transmitted between people in Wuhan, on Jan. 20, 2020, Taiwanese officials had suspected that was the case. They quickly started to screen travelers and initiated stronger restrictions soon after, including quarantines of travelers from China and, later, elsewhere as well. The Taiwanese also masked up early — rationing to ensure everyone could get some of limited supply — worked aggressively to find cases that slipped through, to stomp out local outbreaks.

Even though many travelers had arrived from Wuhan before these measures were put in place, Taiwan quashed the initial spread and has effectively contained the crisis for almost two years.

What didn’t work was the way the United States went about it last year. Travel was initially restricted only from China and late in the game. The ban did not apply to American citizens and was not paired with wide-scale testing at the border and throughout the country. Mr. Biden’s ban has similar problems — it won’t even start until Monday, as if the virus takes the weekend off.

That’s pandemic theatrics, not public health.

Last year, many of the first cases came to the United States from Europe, not China, because it had already spread extensively and tests were rarely conducted on anyone who had not been to Wuhan.

In detecting Omicron, we have a key advantage, by a stroke of luck. For many variants, scientists need to sample the full sequence to clearly distinguish them. Like a few other variants, Omicron has a particular genetic signal that shows up in PCR testing, making it easier to track with our regular testing infrastructure and easier to include tracking this variant as part of a mass testing effort.

South Korea demonstrated the importance of early mass testing. Its first Covid case was announced the same day as the first one in the United States, Jan. 20 of last year. Weeks later, a superspreader event at a South Korean church made it the first country to have a significant outbreak outside of China. Its dense cities and crowded public transportation made it a perfect place for an epidemic to bloom.

However, they were ready with a huge testing system, including free drive-through tests, and aggressive tracing. By the end of March, they had gotten the initial outbreak under control. As of now, the country of over 50 million has had a total of about 3,500 deaths during the entire pandemic — less than a week’s terrible toll in New York during its peak wave in April 2020.

The United States already needs to test more, because of the ongoing Delta surge.

Tragically, one reason South Africa put in place the advanced medical surveillance that found the Omicron variant was to track cases of AIDS, which continues to be a crisis there.

The antiviral cocktail that turned AIDS from a death sentence to a chronic condition was developed by the mid-1990s, but pharmaceutical companies, protected by rich nations, refused to let cheap generic versions be manufactured and sold in many poorer countries — they even sued to stop South Africa from importing any. Millions died before an agreement was finally reached years later after extensive global activism.

The callous mistreatment of South Africa by big pharmaceutical companies continued into this pandemic. Moderna, for example, has run some of its vaccine trials in South Africa but did not donate any to the country or even to Covax, the global vaccine alliance, until much later.

Decades of such policies have contributed to high levels of medical mistrust in South Africa, including vaccine hesitancy. Only 35 percent of the adult population is fully vaccinated despite sufficient supplies. (Vaccine supply problems persist elsewhere in Africa: only about a quarter of even health care workers in the continent are fully-vaccinated — a horrible situation).

It’s possible this variant developed through a persistent infection in an immunocompromised patient, such as someone who may not have been treated properly to control an H.I.V. infection. Such lengthy infections are suspected of having allowed other variants to develop as well.

This is all the more reason that if the developed world is going to impose restrictions on South Africa, and other countries, it should provide them with financial support.

In about two to three weeks, lab research and epidemiological data should start to provide a clearer picture of how transmissible this variant is, how it affects the severity of illness, and whether and how much it can evade some vaccine protection.

If results assuage the worst concerns, officials should roll back restrictions. The public will trust the authorities more with early aggressive action if they know restrictive measures will be kept only as long as necessary. It may even turn out that this threat fizzles out completely, or that the variant causes milder disease.

If the worse fears are confirmed, we need to direct the rest of our arsenal to fighting this threat.

There is good news on that front as well.

BioNTech/Pfizer has already said it could have vaccines targeting this variant in as little as three months. The company, and other vaccine manufacturers, should start to produce them immediately. At worst, they will have wasted a few weeks of effort and can treat it as a dry run for a future rapid effort.

Even if current vaccines lose some effectiveness against preventing Omicron breakthrough cases, it’s reasonable to expect them to maintain a good level of protection against hospitalizations and deaths — something we’ve seen with other variants. This is because preventing breakthrough infections and blocking progression to severe disease involve different parts of the immune system — the latter is more able to keep recognizing a virus and continue working well despite some mutations. Still, we can do much better.

All vaccines are still designed to protect against the original virus that emerged in Wuhan, even though that version is rarely found at this point. The Food and Drug Administration has previously said it was ready to approve variant-specific vaccines without the same scope of trials required for the initial vaccines. The F.D.A. should start getting ready for that possibility.

In other good news, new antiviral drugs that may cut down death rates and hospitalizations in high-risk patients by as much as 90 percent are not affected by mutations in variants because they target enzymes that the virus needs to replicate. At the moment, this recent antiviral drug (yet to be authorized even in the United States) is expensive, though Pfizer has talked of cheaper access for lower- and middle-income countries.

Such drugs need to go wherever there are outbreaks, not be hoarded by wealthy countries with early contracts, and their production or price cannot be held hostage to the vagaries of even more profits by companies that have received substantial taxpayer support and use publicly funded research to develop their drugs.

Wealthier nations must provide financial support, as well, for nonpharmaceutical interventions, such as improved ventilation and air filtering, higher-quality masks, paid sick leave and quarantine.

All this requires leadership and a global outlook. Unlike in the terrible days of early last year, we have an early warning, vaccines, effective drugs, greater understanding of the disease and many painful lessons. It’s time to demonstrate that we learned them.

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