At the beginning of January, almost no one outside China had heard of the pneumonia-like illness the world now knows as Wuhan coronavirus or, more technically, 2019-nCoV.

The close of the month saw more than 11,000 cases confirmed, with counts rising daily. The World Health Organization (WHO) has declared a public health emergency of international concern. Hospitals in the epicenter, the Chinese city of Wuhan, are overwhelmed and turning away patients. No other country has yet experienced Wuhan-like conditions, but findings released last week by researchers in China concluded that 2019-nCoV may be more contagious, and have higher pandemic potential, than the 2003 SARS outbreak. Many public health experts are now arguing that given the scale of transmission, focus should shift from containment to mitigation — minimizing spread rather than expecting we can fully stop it.

Faced with this kind of uncertain risk, policymakers must walk a narrow path between aggressive preparedness and counterproductive alarmism. In emergency management, there is a response principle known as “no regrets”: the idea that in an unpredictable crisis, we should proactively over-prepare, rather than wait and see. Importantly, this does not mean recklessly deploying extreme measures; it means judiciously gearing up worst-case preparedness well before a worst-case outcome is certain. This must be the posture as the world confronts 2019-nCoV.

Novel diseases can often surprise us, as the world learned starkly during the 2014 Ebola outbreak. Previous Ebola outbreaks had all topped out at several hundred cases, and few experts then believed the virus had the potential to reach dramatically larger scales. Because officials initially underestimated the worst-case potential of that outbreak, they made early misjudgments in response strategy that allowed the outbreak to spin out of control. Those misjudgments ultimately produced an Ebola outbreak 67 times as large as any previously seen.

There are similar unknowns around the potential risks posed by 2019-nCoV. While we don’t yet know whether this will go from outbreak to pandemic, we should not discount the kind of low-probability, high-consequence outcome that we saw with Ebola.

In the United States and other developed countries, an outbreak with Wuhan’s level of transmission and severity would badly strain hospitals and clinics (just two years ago, a bad seasonal flu cycle forced overstretched U.S. hospitals to treat patients in hallways and tents). It might lead to ruptures in medical supply chains, because U.S. hospital systems rarely maintain deep enough reserves of protective equipment to contend with such a large unexpected surge in cases (by the way, many of those supplies come from China). And there will be no miracle drug on the horizon: Development and production of new pharmaceutical countermeasures will be measured in years rather than months.

In the developing world, the picture could look even grimmer, as WHO noted when issuing its emergency declaration. Baseline health conditions are worse, which would mean greater vulnerability to a disease that appears most severe in patients with other preexisting health problems. Infection prevention and control practices are almost universally weak in low- and lower-middle-income countries’ health systems, according to the Global Health Security Index rankings. This dramatically elevates the risk of infections among health-care workers and also risks turning health facilities into incubators of transmission.

The world is far from ready for this kind of scenario. So what would a no-regrets approach to mitigating 2019-nCoV entail?

It would mean prudent over-preparation, rather than reckless overreaction. Countries should avoid imposing the public health equivalent of “security theater” — sweeping measures that produce more disruption than actual public-health protection. Draconian travel and trade restrictions, for example, might at best briefly delay the inevitable spread but cannot prevent it. Extreme actions such as banning travelers from China (as the United States has just announced) or sealing land borders (as Russia has done) will worsen panic and stigma but provide scant meaningful protection.

A responsible no-regrets approach by public health authorities and global leaders would instead rapidly organize and finance a robust set of measures to dramatically accelerate health system preparedness, while also planning for policies that could be triggered if a worst-case scenario emerges.

An important starting point is vigorous support to front-line health providers. In both developed and developing countries, a concerted effort is needed to equip them to effectively identify and handle a potential surge in cases. This should include urgent funding of material and training support for essential infection prevention and control practices. A vitally important part of this will be efforts to address supply-chain ruptures and accelerate production and availability of critical medical supplies.

Countries should also plan for extreme contingency scenarios in which normal health facilities become overwhelmed. Health officials should be considering the conditions under which they would trigger crisis-care standards that could guide the prioritization of finite facilities, staff and resources. And they should be planning for scenarios in which isolation and care may have to take place outside overwhelmed official health systems — in community-managed centers or in people’s homes.

Finally, countries should be ready to rapidly stand up an empowered global coordinating platform to lead international action. A clear lesson of Ebola in 2014 is that managing a complex global disease response is not just a matter of public health expertise — it also entails diplomatic outreach, security coordination, operational planning and a fair dose of politics. WHO has a central role to play in this, but the breadth of coordination and decision-making that will be required goes beyond what WHO on its own can cover.

We are at a critical point with this outbreak. Conditions in China have not yet been replicated in other countries — but they soon could be, regardless of attempts to suppress international travel. Decisions taken now will determine whether those health systems are prepared for the wave that may be coming. Policymakers must focus on meaningful mitigation strategies, not symbolic public-health theater.